changeset 1580:cef30252932a

6842687: New I/O: Update Asynchronous I/O API to jsr203/nio2-b101 Reviewed-by: sherman
author alanb
date Sun, 23 Aug 2009 12:53:45 +0100
parents 99a55f6f1cef
children fca3e1a178fd
files make/java/nio/FILES_java.gmk src/share/classes/java/nio/channels/AsynchronousByteChannel.java src/share/classes/java/nio/channels/AsynchronousChannel.java src/share/classes/java/nio/channels/AsynchronousDatagramChannel.java src/share/classes/java/nio/channels/AsynchronousFileChannel.java src/share/classes/java/nio/channels/AsynchronousServerSocketChannel.java src/share/classes/java/nio/channels/AsynchronousSocketChannel.java src/share/classes/java/nio/channels/CompletionHandler.java src/share/classes/java/nio/channels/exceptions src/share/classes/sun/nio/ch/AbstractFuture.java src/share/classes/sun/nio/ch/AsynchronousChannelGroupImpl.java src/share/classes/sun/nio/ch/AsynchronousFileChannelImpl.java src/share/classes/sun/nio/ch/AsynchronousServerSocketChannelImpl.java src/share/classes/sun/nio/ch/AsynchronousSocketChannelImpl.java src/share/classes/sun/nio/ch/CompletedFuture.java src/share/classes/sun/nio/ch/Invoker.java src/share/classes/sun/nio/ch/PendingFuture.java src/share/classes/sun/nio/ch/SimpleAsynchronousDatagramChannelImpl.java src/share/classes/sun/nio/ch/SimpleAsynchronousFileChannelImpl.java src/solaris/classes/sun/nio/ch/EPollPort.java src/solaris/classes/sun/nio/ch/Port.java src/solaris/classes/sun/nio/ch/SolarisEventPort.java src/solaris/classes/sun/nio/ch/UnixAsynchronousServerSocketChannelImpl.java src/solaris/classes/sun/nio/ch/UnixAsynchronousSocketChannelImpl.java src/windows/classes/sun/nio/ch/Iocp.java src/windows/classes/sun/nio/ch/WindowsAsynchronousFileChannelImpl.java src/windows/classes/sun/nio/ch/WindowsAsynchronousServerSocketChannelImpl.java src/windows/classes/sun/nio/ch/WindowsAsynchronousSocketChannelImpl.java src/windows/native/sun/nio/ch/Iocp.c test/java/nio/channels/AsynchronousChannelGroup/GroupOfOne.java test/java/nio/channels/AsynchronousChannelGroup/Identity.java test/java/nio/channels/AsynchronousChannelGroup/Restart.java test/java/nio/channels/AsynchronousChannelGroup/Unbounded.java test/java/nio/channels/AsynchronousDatagramChannel/Basic.java test/java/nio/channels/AsynchronousFileChannel/Basic.java test/java/nio/channels/AsynchronousFileChannel/CustomThreadPool.java test/java/nio/channels/AsynchronousFileChannel/Lock.java test/java/nio/channels/AsynchronousServerSocketChannel/Basic.java test/java/nio/channels/AsynchronousSocketChannel/Basic.java test/java/nio/channels/AsynchronousSocketChannel/DieBeforeComplete.java test/java/nio/channels/AsynchronousSocketChannel/StressLoopback.java test/java/nio/channels/FileChannel/ReleaseOnCloseDeadlock.java
diffstat 42 files changed, 1883 insertions(+), 1648 deletions(-) [+]
line wrap: on
line diff
--- a/make/java/nio/FILES_java.gmk	Sat Aug 22 17:40:18 2009 +0100
+++ b/make/java/nio/FILES_java.gmk	Sun Aug 23 12:53:45 2009 +0100
@@ -160,7 +160,6 @@
 	\
 	sun/nio/ByteBuffered.java \
 	\
-	sun/nio/ch/AbstractFuture.java \
         sun/nio/ch/AbstractPollArrayWrapper.java \
 	sun/nio/ch/AllocatedNativeObject.java \
 	sun/nio/ch/AsynchronousChannelGroupImpl.java \
--- a/src/share/classes/java/nio/channels/AsynchronousByteChannel.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/java/nio/channels/AsynchronousByteChannel.java	Sun Aug 23 12:53:45 2009 +0100
@@ -56,18 +56,18 @@
     /**
      * Reads a sequence of bytes from this channel into the given buffer.
      *
-     * <p> This method initiates an operation to read a sequence of bytes from
-     * this channel into the given buffer. The method returns a {@link Future}
-     * representing the pending result of the operation. The result of the
-     * operation, obtained by invoking the {@code Future} 's {@link
-     * Future#get() get} method, is the number of bytes read or {@code -1} if
-     * all bytes have been read and the channel has reached end-of-stream.
+     * <p> This method initiates an asynchronous read operation to read a
+     * sequence of bytes from this channel into the given buffer. The {@code
+     * handler} parameter is a completion handler that is invoked when the read
+     * operation completes (or fails). The result passed to the completion
+     * handler is the number of bytes read or {@code -1} if no bytes could be
+     * read because the channel has reached end-of-stream.
      *
-     * <p> This method initiates a read operation to read up to <i>r</i> bytes
-     * from the channel, where <i>r</i> is the number of bytes remaining in the
-     * buffer, that is, {@code dst.remaining()} at the time that the read is
-     * attempted. Where <i>r</i> is 0, the read operation completes immediately
-     * with a result of {@code 0} without initiating an I/O operation.
+     * <p> The read operation may read up to <i>r</i> bytes from the channel,
+     * where <i>r</i> is the number of bytes remaining in the buffer, that is,
+     * {@code dst.remaining()} at the time that the read is attempted. Where
+     * <i>r</i> is 0, the read operation completes immediately with a result of
+     * {@code 0} without initiating an I/O operation.
      *
      * <p> Suppose that a byte sequence of length <i>n</i> is read, where
      * <tt>0</tt>&nbsp;<tt>&lt;</tt>&nbsp;<i>n</i>&nbsp;<tt>&lt;=</tt>&nbsp;<i>r</i>.
@@ -79,44 +79,46 @@
      * <i>p</i>&nbsp;<tt>+</tt>&nbsp;<i>n</i>; its limit will not have changed.
      *
      * <p> Buffers are not safe for use by multiple concurrent threads so care
-     * should be taken to not to access the buffer until the operaton has completed.
+     * should be taken to not access the buffer until the operation has
+     * completed.
      *
      * <p> This method may be invoked at any time. Some channel types may not
      * allow more than one read to be outstanding at any given time. If a thread
      * initiates a read operation before a previous read operation has
      * completed then a {@link ReadPendingException} will be thrown.
      *
-     * <p> The <tt>handler</tt> parameter is used to specify a {@link
-     * CompletionHandler}. When the read operation completes the handler's
-     * {@link CompletionHandler#completed completed} method is executed.
-     *
-     *
      * @param   dst
      *          The buffer into which bytes are to be transferred
      * @param   attachment
      *          The object to attach to the I/O operation; can be {@code null}
      * @param   handler
-     *          The completion handler object; can be {@code null}
-     *
-     * @return  A Future representing the result of the operation
+     *          The completion handler
      *
      * @throws  IllegalArgumentException
      *          If the buffer is read-only
      * @throws  ReadPendingException
      *          If the channel does not allow more than one read to be outstanding
      *          and a previous read has not completed
+     * @throws  ShutdownChannelGroupException
+     *          If the channel is associated with a {@link AsynchronousChannelGroup
+     *          group} that has terminated
      */
-    <A> Future<Integer> read(ByteBuffer dst,
-                             A attachment,
-                             CompletionHandler<Integer,? super A> handler);
+    <A> void read(ByteBuffer dst,
+                  A attachment,
+                  CompletionHandler<Integer,? super A> handler);
 
     /**
      * Reads a sequence of bytes from this channel into the given buffer.
      *
-     * <p> An invocation of this method of the form <tt>c.read(dst)</tt>
-     * behaves in exactly the same manner as the invocation
-     * <blockquote><pre>
-     * c.read(dst, null, null);</pre></blockquote>
+     * <p> This method initiates an asynchronous read operation to read a
+     * sequence of bytes from this channel into the given buffer. The method
+     * behaves in exactly the same manner as the {@link
+     * #read(ByteBuffer,Object,CompletionHandler)
+     * read(ByteBuffer,Object,CompletionHandler)} method except that instead
+     * of specifying a completion handler, this method returns a {@code Future}
+     * representing the pending result. The {@code Future}'s {@link Future#get()
+     * get} method returns the number of bytes read or {@code -1} if no bytes
+     * could be read because the channel has reached end-of-stream.
      *
      * @param   dst
      *          The buffer into which bytes are to be transferred
@@ -134,17 +136,17 @@
     /**
      * Writes a sequence of bytes to this channel from the given buffer.
      *
-     * <p> This method initiates an operation to write a sequence of bytes to
-     * this channel from the given buffer. This method returns a {@link
-     * Future} representing the pending result of the operation. The result
-     * of the operation, obtained by invoking the <tt>Future</tt>'s {@link
-     * Future#get() get} method, is the number of bytes written, possibly zero.
+     * <p> This method initiates an asynchronous write operation to write a
+     * sequence of bytes to this channel from the given buffer. The {@code
+     * handler} parameter is a completion handler that is invoked when the write
+     * operation completes (or fails). The result passed to the completion
+     * handler is the number of bytes written.
      *
-     * <p> This method initiates a write operation to write up to <i>r</i> bytes
-     * to the channel, where <i>r</i> is the number of bytes remaining in the
-     * buffer, that is, {@code src.remaining()}  at the moment the write is
-     * attempted. Where <i>r</i> is 0, the write operation completes immediately
-     * with a result of {@code 0} without initiating an I/O operation.
+     * <p> The write operation may write up to <i>r</i> bytes to the channel,
+     * where <i>r</i> is the number of bytes remaining in the buffer, that is,
+     * {@code src.remaining()} at the time that the write is attempted. Where
+     * <i>r</i> is 0, the write operation completes immediately with a result of
+     * {@code 0} without initiating an I/O operation.
      *
      * <p> Suppose that a byte sequence of length <i>n</i> is written, where
      * <tt>0</tt>&nbsp;<tt>&lt;</tt>&nbsp;<i>n</i>&nbsp;<tt>&lt;=</tt>&nbsp;<i>r</i>.
@@ -156,41 +158,43 @@
      * <i>p</i>&nbsp;<tt>+</tt>&nbsp;<i>n</i>; its limit will not have changed.
      *
      * <p> Buffers are not safe for use by multiple concurrent threads so care
-     * should be taken to not to access the buffer until the operaton has completed.
+     * should be taken to not access the buffer until the operation has
+     * completed.
      *
      * <p> This method may be invoked at any time. Some channel types may not
      * allow more than one write to be outstanding at any given time. If a thread
      * initiates a write operation before a previous write operation has
      * completed then a {@link WritePendingException} will be thrown.
      *
-     * <p> The <tt>handler</tt> parameter is used to specify a {@link
-     * CompletionHandler}. When the write operation completes the handler's
-     * {@link CompletionHandler#completed completed} method is executed.
-     *
      * @param   src
      *          The buffer from which bytes are to be retrieved
      * @param   attachment
      *          The object to attach to the I/O operation; can be {@code null}
      * @param   handler
-     *          The completion handler object; can be {@code null}
-     *
-     * @return  A Future representing the result of the operation
+     *          The completion handler object
      *
      * @throws  WritePendingException
      *          If the channel does not allow more than one write to be outstanding
      *          and a previous write has not completed
+     * @throws  ShutdownChannelGroupException
+     *          If the channel is associated with a {@link AsynchronousChannelGroup
+     *          group} that has terminated
      */
-    <A> Future<Integer> write(ByteBuffer src,
-                              A attachment,
-                              CompletionHandler<Integer,? super A> handler);
+    <A> void write(ByteBuffer src,
+                   A attachment,
+                   CompletionHandler<Integer,? super A> handler);
 
     /**
      * Writes a sequence of bytes to this channel from the given buffer.
      *
-     * <p> An invocation of this method of the form <tt>c.write(src)</tt>
-     * behaves in exactly the same manner as the invocation
-     * <blockquote><pre>
-     * c.write(src, null, null);</pre></blockquote>
+     * <p> This method initiates an asynchronous write operation to write a
+     * sequence of bytes to this channel from the given buffer. The method
+     * behaves in exactly the same manner as the {@link
+     * #write(ByteBuffer,Object,CompletionHandler)
+     * write(ByteBuffer,Object,CompletionHandler)} method except that instead
+     * of specifying a completion handler, this method returns a {@code Future}
+     * representing the pending result. The {@code Future}'s {@link Future#get()
+     * get} method returns the number of bytes written.
      *
      * @param   src
      *          The buffer from which bytes are to be retrieved
--- a/src/share/classes/java/nio/channels/AsynchronousChannel.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/java/nio/channels/AsynchronousChannel.java	Sun Aug 23 12:53:45 2009 +0100
@@ -34,7 +34,8 @@
  *
  * <ol>
  * <li><pre>{@link Future}&lt;V&gt; <em>operation</em>(<em>...</em>)</pre></li>
- * <li><pre>Future&lt;V&gt; <em>operation</em>(<em>...</em> A attachment, {@link CompletionHandler}&lt;V,? super A&gt handler)</pre></li>
+ * <li><pre>void <em>operation</em>(<em>...</em> A attachment, {@link
+ *   CompletionHandler}&lt;V,? super A&gt; handler)</pre></li>
  * </ol>
  *
  * where <i>operation</i> is the name of the I/O operation (read or write for
@@ -48,7 +49,7 @@
  * interface may be used to check if the operation has completed, wait for its
  * completion, and to retrieve the result. In the second form, a {@link
  * CompletionHandler} is invoked to consume the result of the I/O operation when
- * it completes, fails, or is cancelled.
+ * it completes or fails.
  *
  * <p> A channel that implements this interface is <em>asynchronously
  * closeable</em>: If an I/O operation is outstanding on the channel and the
@@ -63,33 +64,33 @@
  * <h4>Cancellation</h4>
  *
  * <p> The {@code Future} interface defines the {@link Future#cancel cancel}
- * method to cancel execution of a task.
+ * method to cancel execution. This causes all threads waiting on the result of
+ * the I/O operation to throw {@link java.util.concurrent.CancellationException}.
+ * Whether the underlying I/O operation can be cancelled is highly implementation
+ * specific and therefore not specified. Where cancellation leaves the channel,
+ * or the entity to which it is connected, in an inconsistent state, then the
+ * channel is put into an implementation specific <em>error state</em> that
+ * prevents further attempts to initiate I/O operations that are <i>similar</i>
+ * to the operation that was cancelled. For example, if a read operation is
+ * cancelled but the implementation cannot guarantee that bytes have not been
+ * read from the channel then it puts the channel into an error state; further
+ * attempts to initiate a {@code read} operation cause an unspecified runtime
+ * exception to be thrown. Similarly, if a write operation is cancelled but the
+ * implementation cannot guarantee that bytes have not been written to the
+ * channel then subsequent attempts to initiate a {@code write} will fail with
+ * an unspecified runtime exception.
  *
- * <p> Where the {@code cancel} method is invoked with the {@code
+ * <p> Where the {@link Future#cancel cancel} method is invoked with the {@code
  * mayInterruptIfRunning} parameter set to {@code true} then the I/O operation
- * may be interrupted by closing the channel. This will cause any other I/O
- * operations outstanding on the channel to complete with the exception {@link
- * AsynchronousCloseException}.
- *
- * <p> If a {@code CompletionHandler} is specified when initiating an I/O
- * operation, and the {@code cancel} method is invoked to cancel the I/O
- * operation before it completes, then the {@code CompletionHandler}'s {@link
- * CompletionHandler#cancelled cancelled} method is invoked.
- *
- * <p> If an implementation of this interface supports a means to cancel I/O
- * operations, and where cancellation may leave the channel, or the entity to
- * which it is connected, in an inconsistent state, then the channel is put into
- * an implementation specific <em>error state</em> that prevents further
- * attempts to initiate I/O operations on the channel. For example, if a read
- * operation is cancelled but the implementation cannot guarantee that bytes
- * have not been read from the channel then it puts the channel into error state
- * state; further attempts to initiate a {@code read} operation causes an
- * unspecified runtime exception to be thrown.
+ * may be interrupted by closing the channel. In that case all threads waiting
+ * on the result of the I/O operation throw {@code CancellationException} and
+ * any other I/O operations outstanding on the channel complete with the
+ * exception {@link AsynchronousCloseException}.
  *
  * <p> Where the {@code cancel} method is invoked to cancel read or write
- * operations then it recommended that all buffers used in the I/O operations be
- * discarded or care taken to ensure that the buffers are not accessed while the
- * channel remains open.
+ * operations then it is recommended that all buffers used in the I/O operations
+ * be discarded or care taken to ensure that the buffers are not accessed while
+ * the channel remains open.
  *
  *  @since 1.7
  */
@@ -102,7 +103,7 @@
      *
      * <p> Any outstanding asynchronous operations upon this channel will
      * complete with the exception {@link AsynchronousCloseException}. After a
-     * channel is closed then further attempts to initiate asynchronous I/O
+     * channel is closed, further attempts to initiate asynchronous I/O
      * operations complete immediately with cause {@link ClosedChannelException}.
      *
      * <p>  This method otherwise behaves exactly as specified by the {@link
--- a/src/share/classes/java/nio/channels/AsynchronousDatagramChannel.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/java/nio/channels/AsynchronousDatagramChannel.java	Sun Aug 23 12:53:45 2009 +0100
@@ -109,19 +109,13 @@
  *  // print the source address of all packets that we receive
  *  dc.receive(buffer, buffer, new CompletionHandler&lt;SocketAddress,ByteBuffer&gt;() {
  *      public void completed(SocketAddress sa, ByteBuffer buffer) {
- *          try {
- *               System.out.println(sa);
- *
- *               buffer.clear();
- *               dc.receive(buffer, buffer, this);
- *           } catch (...) { ... }
+ *          System.out.println(sa);
+ *          buffer.clear();
+ *          dc.receive(buffer, buffer, this);
  *      }
  *      public void failed(Throwable exc, ByteBuffer buffer) {
  *          ...
  *      }
- *      public void cancelled(ByteBuffer buffer) {
- *          ...
- *      }
  *  });
  * </pre>
  *
@@ -314,10 +308,10 @@
     /**
      * Receives a datagram via this channel.
      *
-     * <p> This method initiates the receiving of a datagram, returning a
-     * {@code Future} representing the pending result of the operation.
-     * The {@code Future}'s {@link Future#get() get} method returns
-     * the source address of the datagram upon successful completion.
+     * <p> This method initiates the receiving of a datagram into the given
+     * buffer. The {@code handler} parameter is a completion handler that is
+     * invoked when the receive operation completes (or fails). The result
+     * passed to the completion handler is the datagram's source address.
      *
      * <p> The datagram is transferred into the given byte buffer starting at
      * its current position, as if by a regular {@link AsynchronousByteChannel#read
@@ -350,28 +344,26 @@
      * @param   attachment
      *          The object to attach to the I/O operation; can be {@code null}
      * @param   handler
-     *          The handler for consuming the result; can be {@code null}
-     *
-     * @return  a {@code Future} object representing the pending result
+     *          The handler for consuming the result
      *
      * @throws  IllegalArgumentException
      *          If the timeout is negative or the buffer is read-only
      * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
+     *          If the channel group has terminated
      */
-    public abstract <A> Future<SocketAddress> receive(ByteBuffer dst,
-                                                      long timeout,
-                                                      TimeUnit unit,
-                                                      A attachment,
-                                                      CompletionHandler<SocketAddress,? super A> handler);
+    public abstract <A> void receive(ByteBuffer dst,
+                                     long timeout,
+                                     TimeUnit unit,
+                                     A attachment,
+                                     CompletionHandler<SocketAddress,? super A> handler);
 
     /**
      * Receives a datagram via this channel.
      *
-     * <p> This method initiates the receiving of a datagram, returning a
-     * {@code Future} representing the pending result of the operation.
-     * The {@code Future}'s {@link Future#get() get} method returns
-     * the source address of the datagram upon successful completion.
+     * <p> This method initiates the receiving of a datagram into the given
+     * buffer. The {@code handler} parameter is a completion handler that is
+     * invoked when the receive operation completes (or fails). The result
+     * passed to the completion handler is the datagram's source address.
      *
      * <p> This method is equivalent to invoking {@link
      * #receive(ByteBuffer,long,TimeUnit,Object,CompletionHandler)} with a
@@ -382,34 +374,30 @@
      * @param   attachment
      *          The object to attach to the I/O operation; can be {@code null}
      * @param   handler
-     *          The handler for consuming the result; can be {@code null}
-     *
-     * @return  a {@code Future} object representing the pending result
+     *          The handler for consuming the result
      *
      * @throws  IllegalArgumentException
      *          If the buffer is read-only
      * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
+     *          If the channel group has terminated
      */
-    public final <A> Future<SocketAddress> receive(ByteBuffer dst,
-                                                   A attachment,
-                                                   CompletionHandler<SocketAddress,? super A> handler)
+    public final <A> void receive(ByteBuffer dst,
+                                  A attachment,
+                                  CompletionHandler<SocketAddress,? super A> handler)
     {
-        return receive(dst, 0L, TimeUnit.MILLISECONDS, attachment, handler);
+        receive(dst, 0L, TimeUnit.MILLISECONDS, attachment, handler);
     }
 
     /**
      * Receives a datagram via this channel.
      *
-     * <p> This method initiates the receiving of a datagram, returning a
-     * {@code Future} representing the pending result of the operation.
-     * The {@code Future}'s {@link Future#get() get} method returns
-     * the source address of the datagram upon successful completion.
-     *
-     * <p> This method is equivalent to invoking {@link
-     * #receive(ByteBuffer,long,TimeUnit,Object,CompletionHandler)} with a
-     * timeout of {@code 0L}, and an attachment and completion handler
-     * of {@code null}.
+     * <p> This method initiates the receiving of a datagram into the given
+     * buffer. The method behaves in exactly the same manner as the {@link
+     * #receive(ByteBuffer,Object,CompletionHandler)
+     * receive(ByteBuffer,Object,CompletionHandler)} method except that instead
+     * of specifying a completion handler, this method returns a {@code Future}
+     * representing the pending result. The {@code Future}'s {@link Future#get()
+     * get} method returns the datagram's source address.
      *
      * @param   dst
      *          The buffer into which the datagram is to be transferred
@@ -419,84 +407,19 @@
      * @throws  IllegalArgumentException
      *          If the buffer is read-only
      */
-    public final <A> Future<SocketAddress> receive(ByteBuffer dst) {
-        return receive(dst, 0L, TimeUnit.MILLISECONDS, null, null);
-    }
+    public abstract Future<SocketAddress> receive(ByteBuffer dst);
 
     /**
      * Sends a datagram via this channel.
      *
-     * <p> This method initiates sending of a datagram, returning a
-     * {@code Future} representing the pending result of the operation.
-     * The operation sends the remaining bytes in the given buffer as a single
-     * datagram to the given target address. The result of the operation, obtained
-     * by invoking the {@code Future}'s {@link Future#get() get}
-     * method, is the number of bytes sent.
+     * <p> This method initiates sending of a datagram from the given buffer to
+     * the given address. The {@code handler} parameter is a completion handler
+     * that is invoked when the send completes (or fails). The result passed to
+     * the completion handler is the number of bytes sent.
      *
-     * <p> The datagram is transferred from the byte buffer as if by a regular
-     * {@link AsynchronousByteChannel#write write} operation.
-     *
-     * <p> If a timeout is specified and the timeout elapses before the operation
-     * completes then the operation completes with the exception {@link
-     * InterruptedByTimeoutException}. When a timeout elapses then the state of
-     * the {@link ByteBuffer} is not defined. The buffers should be discarded or
-     * at least care must be taken to ensure that the buffer is not accessed
-     * while the channel remains open.
-     *
-     * <p> If there is a security manager installed and the channel is not
-     * connected then this method verifies that the target address and port number
-     * are permitted by the security manager's {@link SecurityManager#checkConnect
-     * checkConnect} method.  The overhead of this security check can be avoided
-     * by first connecting the socket via the {@link #connect connect} method.
-     *
-     * @param   src
-     *          The buffer containing the datagram to be sent
-     * @param   target
-     *          The address to which the datagram is to be sent
-     * @param   timeout
-     *          The timeout, or {@code 0L} for no timeout
-     * @param   unit
-     *          The time unit of the {@code timeout} argument
-     * @param   attachment
-     *          The object to attach to the I/O operation; can be {@code null}
-     * @param   handler
-     *          The handler for consuming the result; can be {@code null}
-     *
-     * @return  a {@code Future} object representing the pending result
-     *
-     * @throws  UnresolvedAddressException
-     *          If the given remote address is not fully resolved
-     * @throws  UnsupportedAddressTypeException
-     *          If the type of the given remote address is not supported
-     * @throws  IllegalArgumentException
-     *          If the timeout is negative, or if the channel's socket is
-     *          connected to an address that is not equal to {@code target}
-     * @throws  SecurityException
-     *          If a security manager has been installed and it does not permit
-     *          datagrams to be sent to the given address
-     * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
-     */
-    public abstract <A> Future<Integer> send(ByteBuffer src,
-                                             SocketAddress target,
-                                             long timeout,
-                                             TimeUnit unit,
-                                             A attachment,
-                                             CompletionHandler<Integer,? super A> handler);
-
-    /**
-     * Sends a datagram via this channel.
-     *
-     * <p> This method initiates sending of a datagram, returning a
-     * {@code Future} representing the pending result of the operation.
-     * The operation sends the remaining bytes in the given buffer as a single
-     * datagram to the given target address. The result of the operation, obtained
-     * by invoking the {@code Future}'s {@link Future#get() get}
-     * method, is the number of bytes sent.
-     *
-     * <p> This method is equivalent to invoking {@link
-     * #send(ByteBuffer,SocketAddress,long,TimeUnit,Object,CompletionHandler)}
-     * with a timeout of {@code 0L}.
+     * <p> Otherwise this method works in the same manner as the {@link
+     * AsynchronousByteChannel#write(ByteBuffer,Object,CompletionHandler)}
+     * method.
      *
      * @param   src
      *          The buffer containing the datagram to be sent
@@ -505,9 +428,7 @@
      * @param   attachment
      *          The object to attach to the I/O operation; can be {@code null}
      * @param   handler
-     *          The handler for consuming the result; can be {@code null}
-     *
-     * @return  a {@code Future} object representing the pending result
+     *          The handler for consuming the result
      *
      * @throws  UnresolvedAddressException
      *          If the given remote address is not fully resolved
@@ -520,30 +441,23 @@
      *          If a security manager has been installed and it does not permit
      *          datagrams to be sent to the given address
      * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
+     *          If the channel group has terminated
      */
-    public final <A> Future<Integer> send(ByteBuffer src,
-                                          SocketAddress target,
-                                          A attachment,
-                                          CompletionHandler<Integer,? super A> handler)
-    {
-        return send(src, target, 0L, TimeUnit.MILLISECONDS, attachment, handler);
-    }
+    public abstract <A> void send(ByteBuffer src,
+                                  SocketAddress target,
+                                  A attachment,
+                                  CompletionHandler<Integer,? super A> handler);
 
     /**
      * Sends a datagram via this channel.
      *
-     * <p> This method initiates sending of a datagram, returning a
-     * {@code Future} representing the pending result of the operation.
-     * The operation sends the remaining bytes in the given buffer as a single
-     * datagram to the given target address. The result of the operation, obtained
-     * by invoking the {@code Future}'s {@link Future#get() get}
-     * method, is the number of bytes sent.
-     *
-     * <p> This method is equivalent to invoking {@link
-     * #send(ByteBuffer,SocketAddress,long,TimeUnit,Object,CompletionHandler)}
-     * with a timeout of {@code 0L} and an attachment and completion handler
-     * of {@code null}.
+     * <p> This method initiates sending of a datagram from the given buffer to
+     * the given address. The method behaves in exactly the same manner as the
+     * {@link #send(ByteBuffer,SocketAddress,Object,CompletionHandler)
+     * send(ByteBuffer,SocketAddress,Object,CompletionHandler)} method except
+     * that instead of specifying a completion handler, this method returns a
+     * {@code Future} representing the pending result. The {@code Future}'s
+     * {@link Future#get() get} method returns the number of bytes sent.
      *
      * @param   src
      *          The buffer containing the datagram to be sent
@@ -563,17 +477,15 @@
      *          If a security manager has been installed and it does not permit
      *          datagrams to be sent to the given address
      */
-    public final Future<Integer> send(ByteBuffer src, SocketAddress target) {
-        return send(src, target, 0L, TimeUnit.MILLISECONDS, null, null);
-    }
+    public abstract Future<Integer> send(ByteBuffer src, SocketAddress target);
 
     /**
      * Receives a datagram via this channel.
      *
-     * <p> This method initiates the receiving of a datagram, returning a
-     * {@code Future} representing the pending result of the operation.
-     * The {@code Future}'s {@link Future#get() get} method returns
-     * the number of bytes transferred upon successful completion.
+     * <p> This method initiates the receiving of a datagram into the given
+     * buffer. The {@code handler} parameter is a completion handler that is
+     * invoked when the receive operation completes (or fails). The result
+     * passed to the completion handler is number of bytes read.
      *
      * <p> This method may only be invoked if this channel is connected, and it
      * only accepts datagrams from the peer that the channel is connected too.
@@ -599,120 +511,62 @@
      * @param   attachment
      *          The object to attach to the I/O operation; can be {@code null}
      * @param   handler
-     *          The handler for consuming the result; can be {@code null}
-     *
-     * @return  a {@code Future} object representing the pending result
+     *          The handler for consuming the result
      *
      * @throws  IllegalArgumentException
      *          If the timeout is negative or buffer is read-only
      * @throws  NotYetConnectedException
      *          If this channel is not connected
      * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
+     *          If the channel group has terminated
      */
-    public abstract <A> Future<Integer> read(ByteBuffer dst,
-                                             long timeout,
-                                             TimeUnit unit,
-                                             A attachment,
-                                             CompletionHandler<Integer,? super A> handler);
+    public abstract <A> void read(ByteBuffer dst,
+                                  long timeout,
+                                  TimeUnit unit,
+                                  A attachment,
+                                  CompletionHandler<Integer,? super A> handler);
 
     /**
      * @throws  NotYetConnectedException
      *          If this channel is not connected
      * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
+     *          If the channel group has terminated
      */
     @Override
-    public final <A> Future<Integer> read(ByteBuffer dst,
-                                          A attachment,
-                                          CompletionHandler<Integer,? super A> handler)
+    public final <A> void read(ByteBuffer dst,
+                               A attachment,
+                               CompletionHandler<Integer,? super A> handler)
     {
-        return read(dst, 0L, TimeUnit.MILLISECONDS, attachment, handler);
+        read(dst, 0L, TimeUnit.MILLISECONDS, attachment, handler);
     }
 
     /**
      * @throws  NotYetConnectedException
      *          If this channel is not connected
      * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
+     *          If the channel group has terminated
      */
     @Override
-    public final Future<Integer> read(ByteBuffer dst) {
-        return read(dst, 0L, TimeUnit.MILLISECONDS, null, null);
-    }
-
-    /**
-     * Writes a datagram to this channel.
-     *
-     * <p> This method initiates sending of a datagram, returning a
-     * {@code Future} representing the pending result of the operation.
-     * The operation sends the remaining bytes in the given buffer as a single
-     * datagram. The result of the operation, obtained by invoking the
-     * {@code Future}'s {@link Future#get() get} method, is the
-     * number of bytes sent.
-     *
-     * <p> The datagram is transferred from the byte buffer as if by a regular
-     * {@link AsynchronousByteChannel#write write} operation.
-     *
-     * <p> This method may only be invoked if this channel is connected,
-     * in which case it sends datagrams directly to the socket's peer.  Otherwise
-     * it behaves exactly as specified in the {@link
-     * AsynchronousByteChannel} interface.
-     *
-     * <p> If a timeout is specified and the timeout elapses before the operation
-     * completes then the operation completes with the exception {@link
-     * InterruptedByTimeoutException}. When a timeout elapses then the state of
-     * the {@link ByteBuffer} is not defined. The buffers should be discarded or
-     * at least care must be taken to ensure that the buffer is not accessed
-     * while the channel remains open.
-     *
-     * @param   src
-     *          The buffer containing the datagram to be sent
-     * @param   timeout
-     *          The timeout, or {@code 0L} for no timeout
-     * @param   unit
-     *          The time unit of the {@code timeout} argument
-     * @param   attachment
-     *          The object to attach to the I/O operation; can be {@code null}
-     * @param   handler
-     *          The handler for consuming the result; can be {@code null}
-     *
-     * @return  a {@code Future} object representing the pending result
-     *
-     * @throws  IllegalArgumentException
-     *          If the timeout is negative
-     * @throws  NotYetConnectedException
-     *          If this channel is not connected
-     * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
-     */
-    public abstract <A> Future<Integer> write(ByteBuffer src,
-                                              long timeout,
-                                              TimeUnit unit,
-                                              A attachment,
-                                              CompletionHandler<Integer,? super A> handler);
-    /**
-     * @throws  NotYetConnectedException
-     *          If this channel is not connected
-     * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
-     */
-    @Override
-    public final <A> Future<Integer> write(ByteBuffer src,
-                                           A attachment,
-                                           CompletionHandler<Integer,? super A> handler)
-    {
-        return write(src, 0L, TimeUnit.MILLISECONDS, attachment, handler);
-    }
+    public abstract Future<Integer> read(ByteBuffer dst);
 
     /**
      * @throws  NotYetConnectedException
      *          If this channel is not connected
      * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
+     *          If the channel group has terminated
      */
     @Override
-    public final Future<Integer> write(ByteBuffer src) {
-        return write(src, 0L, TimeUnit.MILLISECONDS, null, null);
-    }
+    public abstract <A> void  write(ByteBuffer src,
+                                    A attachment,
+                                    CompletionHandler<Integer,? super A> handler);
+
+
+    /**
+     * @throws  NotYetConnectedException
+     *          If this channel is not connected
+     * @throws  ShutdownChannelGroupException
+     *          If the channel group has terminated
+     */
+    @Override
+    public abstract Future<Integer> write(ByteBuffer src);
 }
--- a/src/share/classes/java/nio/channels/AsynchronousFileChannel.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/java/nio/channels/AsynchronousFileChannel.java	Sun Aug 23 12:53:45 2009 +0100
@@ -48,7 +48,12 @@
  *
  * <p> An asynchronous file channel does not have a <i>current position</i>
  * within the file. Instead, the file position is specified to each read and
- * write operation.
+ * write methd that initiate asynchronous operations. A {@link CompletionHandler}
+ * is specified as a parameter and is invoked to consume the result of the I/O
+ * operation. This class also defines read and write methods that initiate
+ * asynchronous operations, returning a {@link Future} to represent the pending
+ * result of the operation. The {@code Future} may be used to check if the
+ * operation has completed, to wait for its completion.
  *
  * <p> In addition to read and write operations, this class defines the
  * following operations: </p>
@@ -59,18 +64,11 @@
  *   out</i>} to the underlying storage device, ensuring that data are not
  *   lost in the event of a system crash.  </p></li>
  *
- *   <li><p> A region of a file may be {@link FileLock <i>locked</i>}
- *   against access by other programs.  </p></li>
+ *   <li><p> A region of a file may be {@link #lock <i>locked</i>} against
+ *   access by other programs.  </p></li>
  *
  * </ul>
  *
- * <p> The {@link #read read}, {@link #write write}, and {@link #lock lock}
- * methods defined by this class are asynchronous  and return a {@link Future}
- * to represent the pending result of the operation. This may be used to check
- * if the operation has completed, to wait for its completion, and to retrieve
- * the result. These method may optionally specify a {@link CompletionHandler}
- * that is invoked to consume the result of the I/O operation when it completes.
- *
  * <p> An {@code AsynchronousFileChannel} is associated with a thread pool to
  * which tasks are submitted to handle I/O events and dispatch to completion
  * handlers that consume the results of I/O operations on the channel. The
@@ -123,22 +121,6 @@
     }
 
     /**
-     * Closes this channel.
-     *
-     * <p> If this channel is associated with its own thread pool then closing
-     * the channel causes the thread pool to shutdown after all actively
-     * executing completion handlers have completed. No attempt is made to stop
-     * or interrupt actively completion handlers.
-     *
-     * <p> This method otherwise behaves exactly as specified by the {@link
-     * AsynchronousChannel} interface.
-     *
-     * @throws  IOException     {@inheritDoc}
-     */
-    @Override
-    public abstract void close() throws IOException;
-
-    /**
      * Opens or creates a file for reading and/or writing, returning an
      * asynchronous file channel to access the file.
      *
@@ -215,9 +197,8 @@
      * should be taken when configuring the {@code Executor}. Minimally it
      * should support an unbounded work queue and should not run tasks on the
      * caller thread of the {@link ExecutorService#execute execute} method.
-     * {@link #close Closing} the channel results in the orderly {@link
-     * ExecutorService#shutdown shutdown} of the executor service. Shutting down
-     * the executor service by other means results in unspecified behavior.
+     * Shutting down the executor service while the channel is open results in
+     * unspecified behavior.
      *
      * <p> The {@code attrs} parameter is an optional array of file {@link
      * FileAttribute file-attributes} to set atomically when creating the file.
@@ -276,7 +257,8 @@
      * <p> An invocation of this method behaves in exactly the same way as the
      * invocation
      * <pre>
-     *     ch.{@link #open(Path,Set,ExecutorService,FileAttribute[]) open}(file, opts, null, new FileAttribute&lt;?&gt;[0]);
+     *     ch.{@link #open(Path,Set,ExecutorService,FileAttribute[])
+     *       open}(file, opts, null, new FileAttribute&lt;?&gt;[0]);
      * </pre>
      * where {@code opts} is a {@code Set} containing the options specified to
      * this method.
@@ -405,10 +387,11 @@
     /**
      * Acquires a lock on the given region of this channel's file.
      *
-     * <p> This method initiates an operation to acquire a lock on the given region
-     * of this channel's file. The method returns a {@code Future} representing
-     * the pending result of the operation. Its {@link Future#get() get}
-     * method returns the {@link FileLock} on successful completion.
+     * <p> This method initiates an operation to acquire a lock on the given
+     * region of this channel's file. The {@code handler} parameter is a
+     * completion handler that is invoked when the lock is acquired (or the
+     * operation fails). The result passed to the completion handler is the
+     * resulting {@code FileLock}.
      *
      * <p> The region specified by the {@code position} and {@code size}
      * parameters need not be contained within, or even overlap, the actual
@@ -455,9 +438,7 @@
      * @param   attachment
      *          The object to attach to the I/O operation; can be {@code null}
      * @param   handler
-     *          The handler for consuming the result; can be {@code null}
-     *
-     * @return  a {@code Future} object representing the pending result
+     *          The handler for consuming the result
      *
      * @throws  OverlappingFileLockException
      *          If a lock that overlaps the requested region is already held by
@@ -466,26 +447,24 @@
      * @throws  IllegalArgumentException
      *          If the preconditions on the parameters do not hold
      * @throws  NonReadableChannelException
-     *          If {@code shared} is true this channel but was not opened for reading
+     *          If {@code shared} is true but this channel was not opened for reading
      * @throws  NonWritableChannelException
      *          If {@code shared} is false but this channel was not opened for writing
-     * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, the channel is closed, and the channel
-     *          was originally created with its own thread pool
      */
-    public abstract <A> Future<FileLock> lock(long position,
-                                              long size,
-                                              boolean shared,
-                                              A attachment,
-                                              CompletionHandler<FileLock,? super A> handler);
+    public abstract <A> void lock(long position,
+                                  long size,
+                                  boolean shared,
+                                  A attachment,
+                                  CompletionHandler<FileLock,? super A> handler);
 
     /**
      * Acquires an exclusive lock on this channel's file.
      *
-     * <p> This method initiates an operation to acquire an exclusive lock on this
-     * channel's file. The method returns a {@code Future} representing
-     * the pending result of the operation. Its {@link Future#get() get}
-     * method returns the {@link FileLock} on successful completion.
+     * <p> This method initiates an operation to acquire a lock on the given
+     * region of this channel's file. The {@code handler} parameter is a
+     * completion handler that is invoked when the lock is acquired (or the
+     * operation fails). The result passed to the completion handler is the
+     * resulting {@code FileLock}.
      *
      * <p> An invocation of this method of the form {@code ch.lock(att,handler)}
      * behaves in exactly the same way as the invocation
@@ -496,7 +475,70 @@
      * @param   attachment
      *          The object to attach to the I/O operation; can be {@code null}
      * @param   handler
-     *          The handler for consuming the result; can be {@code null}
+     *          The handler for consuming the result
+     *
+     * @throws  OverlappingFileLockException
+     *          If a lock is already held by this Java virtual machine, or there
+     *          is already a pending attempt to lock a region
+     * @throws  NonWritableChannelException
+     *          If this channel was not opened for writing
+     */
+    public final <A> void lock(A attachment,
+                               CompletionHandler<FileLock,? super A> handler)
+    {
+        lock(0L, Long.MAX_VALUE, false, attachment, handler);
+    }
+
+    /**
+     * Acquires a lock on the given region of this channel's file.
+     *
+     * <p> This method initiates an operation to acquire a lock on the given
+     * region of this channel's file.  The method behaves in exactly the same
+     * manner as the {@link #lock(long, long, boolean, Object, CompletionHandler)}
+     * method except that instead of specifying a completion handler, this
+     * method returns a {@code Future} representing the pending result. The
+     * {@code Future}'s {@link Future#get() get} method returns the {@link
+     * FileLock} on successful completion.
+     *
+     * @param   position
+     *          The position at which the locked region is to start; must be
+     *          non-negative
+     * @param   size
+     *          The size of the locked region; must be non-negative, and the sum
+     *          {@code position}&nbsp;+&nbsp;{@code size} must be non-negative
+     * @param   shared
+     *          {@code true} to request a shared lock, in which case this
+     *          channel must be open for reading (and possibly writing);
+     *          {@code false} to request an exclusive lock, in which case this
+     *          channel must be open for writing (and possibly reading)
+     *
+     * @return  a {@code Future} object representing the pending result
+     *
+     * @throws  OverlappingFileLockException
+     *          If a lock is already held by this Java virtual machine, or there
+     *          is already a pending attempt to lock a region
+     * @throws  IllegalArgumentException
+     *          If the preconditions on the parameters do not hold
+     * @throws  NonReadableChannelException
+     *          If {@code shared} is true but this channel was not opened for reading
+     * @throws  NonWritableChannelException
+     *          If {@code shared} is false but this channel was not opened for writing
+     */
+    public abstract Future<FileLock> lock(long position, long size, boolean shared);
+
+    /**
+     * Acquires an exclusive lock on this channel's file.
+     *
+     * <p> This method initiates an operation to acquire an exclusive lock on this
+     * channel's file. The method returns a {@code Future} representing the
+     * pending result of the operation. The {@code Future}'s {@link Future#get()
+     * get} method returns the {@link FileLock} on successful completion.
+     *
+     * <p> An invocation of this method behaves in exactly the same way as the
+     * invocation
+     * <pre>
+     *     ch.{@link #lock(long,long,boolean) lock}(0L, Long.MAX_VALUE, false)
+     * </pre>
      *
      * @return  a {@code Future} object representing the pending result
      *
@@ -505,40 +547,9 @@
      *          is already a pending attempt to lock a region
      * @throws  NonWritableChannelException
      *          If this channel was not opened for writing
-     * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, the channel is closed, and the channel
-     *          was originally created with its own thread pool
-     */
-    public final <A> Future<FileLock> lock(A attachment,
-                                           CompletionHandler<FileLock,? super A> handler)
-    {
-        return lock(0L, Long.MAX_VALUE, false, attachment, handler);
-    }
-
-    /**
-     * Acquires an exclusive lock on this channel's file.
-     *
-     * <p> This method initiates an operation to acquire an exclusive lock on this
-     * channel's file. The method returns a {@code Future} representing the
-     * pending result of the operation. Its {@link Future#get() get} method
-     * returns the {@link FileLock} on successful completion.
-     *
-     * <p> An invocation of this method behaves in exactly the same way as the
-     * invocation
-     * <pre>
-     *     ch.{@link #lock(long,long,boolean,Object,CompletionHandler) lock}(0L, Long.MAX_VALUE, false, null, null)
-     * </pre>
-     *
-     * @return  A {@code Future} object representing the pending result
-     *
-     * @throws  OverlappingFileLockException
-     *          If a lock is already held by this Java virtual machine, or there
-     *          is already a pending attempt to lock a region
-     * @throws  NonWritableChannelException
-     *          If this channel was not opened for writing
      */
     public final Future<FileLock> lock() {
-        return lock(0L, Long.MAX_VALUE, false, null, null);
+        return lock(0L, Long.MAX_VALUE, false);
     }
 
     /**
@@ -576,7 +587,7 @@
      *          blocked in this method and is attempting to lock an overlapping
      *          region of the same file
      * @throws  NonReadableChannelException
-     *          If {@code shared} is true this channel but was not opened for reading
+     *          If {@code shared} is true but this channel was not opened for reading
      * @throws  NonWritableChannelException
      *          If {@code shared} is false but this channel was not opened for writing
      *
@@ -629,11 +640,10 @@
      * starting at the given file position.
      *
      * <p> This method initiates the reading of a sequence of bytes from this
-     * channel into the given buffer, starting at the given file position. This
-     * method returns a {@code Future} representing the pending result of the
-     * operation. The Future's {@link Future#get() get} method returns the
-     * number of bytes read or {@code -1} if the given position is greater than
-     * or equal to the file's size at the time that the read is attempted.
+     * channel into the given buffer, starting at the given file position. The
+     * result of the read is the number of bytes read or {@code -1} if the given
+     * position is greater than or equal to the file's size at the time that the
+     * read is attempted.
      *
      * <p> This method works in the same manner as the {@link
      * AsynchronousByteChannel#read(ByteBuffer,Object,CompletionHandler)}
@@ -649,22 +659,17 @@
      * @param   attachment
      *          The object to attach to the I/O operation; can be {@code null}
      * @param   handler
-     *          The handler for consuming the result; can be {@code null}
-     *
-     * @return  A {@code Future} object representing the pending result
+     *          The handler for consuming the result
      *
      * @throws  IllegalArgumentException
      *          If the position is negative or the buffer is read-only
      * @throws  NonReadableChannelException
      *          If this channel was not opened for reading
-     * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, the channel is closed, and the channel
-     *          was originally created with its own thread pool
      */
-    public abstract <A> Future<Integer> read(ByteBuffer dst,
-                                             long position,
-                                             A attachment,
-                                             CompletionHandler<Integer,? super A> handler);
+    public abstract <A> void read(ByteBuffer dst,
+                                  long position,
+                                  A attachment,
+                                  CompletionHandler<Integer,? super A> handler);
 
     /**
      * Reads a sequence of bytes from this channel into the given buffer,
@@ -673,13 +678,15 @@
      * <p> This method initiates the reading of a sequence of bytes from this
      * channel into the given buffer, starting at the given file position. This
      * method returns a {@code Future} representing the pending result of the
-     * operation. The Future's {@link Future#get() get} method returns the
-     * number of bytes read or {@code -1} if the given position is greater
+     * operation. The {@code Future}'s {@link Future#get() get} method returns
+     * the number of bytes read or {@code -1} if the given position is greater
      * than or equal to the file's size at the time that the read is attempted.
      *
-     * <p> This method is equivalent to invoking {@link
-     * #read(ByteBuffer,long,Object,CompletionHandler)} with the {@code attachment}
-     * and handler parameters set to {@code null}.
+     * <p> This method works in the same manner as the {@link
+     * AsynchronousByteChannel#read(ByteBuffer)} method, except that bytes are
+     * read starting at the given file position. If the given file position is
+     * greater than the file's size at the time that the read is attempted then
+     * no bytes are read.
      *
      * @param   dst
      *          The buffer into which bytes are to be transferred
@@ -694,20 +701,12 @@
      * @throws  NonReadableChannelException
      *          If this channel was not opened for reading
      */
-    public final Future<Integer> read(ByteBuffer dst, long position) {
-        return read(dst, position, null, null);
-    }
+    public abstract Future<Integer> read(ByteBuffer dst, long position);
 
     /**
      * Writes a sequence of bytes to this channel from the given buffer, starting
      * at the given file position.
      *
-     * <p> This method initiates the writing of a sequence of bytes to this channel
-     * from the given buffer, starting at the given file position. The method
-     * returns a {@code Future} representing the pending result of the write
-     * operation. The Future's {@link Future#get() get} method returns the
-     * number of bytes written.
-     *
      * <p> This method works in the same manner as the {@link
      * AsynchronousByteChannel#write(ByteBuffer,Object,CompletionHandler)}
      * method, except that bytes are written starting at the given file position.
@@ -724,36 +723,35 @@
      * @param   attachment
      *          The object to attach to the I/O operation; can be {@code null}
      * @param   handler
-     *          The handler for consuming the result; can be {@code null}
-     *
-     * @return  A {@code Future} object representing the pending result
+     *          The handler for consuming the result
      *
      * @throws  IllegalArgumentException
      *          If the position is negative
      * @throws  NonWritableChannelException
      *          If this channel was not opened for writing
-     * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, the channel is closed, and the channel
-     *          was originally created with its own thread pool
      */
-    public abstract <A> Future<Integer> write(ByteBuffer src,
-                                              long position,
-                                              A attachment,
-                                              CompletionHandler<Integer,? super A> handler);
+    public abstract <A> void write(ByteBuffer src,
+                                   long position,
+                                   A attachment,
+                                   CompletionHandler<Integer,? super A> handler);
 
     /**
      * Writes a sequence of bytes to this channel from the given buffer, starting
      * at the given file position.
      *
-     * <p> This method initiates the writing of a sequence of bytes to this channel
-     * from the given buffer, starting at the given file position. The method
-     * returns a {@code Future} representing the pending result of the write
-     * operation. The Future's {@link Future#get() get} method returns the
-     * number of bytes written.
+     * <p> This method initiates the writing of a sequence of bytes to this
+     * channel from the given buffer, starting at the given file position. The
+     * method returns a {@code Future} representing the pending result of the
+     * write operation. The {@code Future}'s {@link Future#get() get} method
+     * returns the number of bytes written.
      *
-     * <p> This method is equivalent to invoking {@link
-     * #write(ByteBuffer,long,Object,CompletionHandler)} with the {@code attachment}
-     * and handler parameters set to {@code null}.
+     * <p> This method works in the same manner as the {@link
+     * AsynchronousByteChannel#write(ByteBuffer)} method, except that bytes are
+     * written starting at the given file position. If the given position is
+     * greater than the file's size, at the time that the write is attempted,
+     * then the file will be grown to accommodate the new bytes; the values of
+     * any bytes between the previous end-of-file and the newly-written bytes
+     * are unspecified.
      *
      * @param   src
      *          The buffer from which bytes are to be transferred
@@ -768,7 +766,5 @@
      * @throws  NonWritableChannelException
      *          If this channel was not opened for writing
      */
-    public final Future<Integer> write(ByteBuffer src, long position) {
-        return write(src, position, null, null);
-    }
+    public abstract Future<Integer> write(ByteBuffer src, long position);
 }
--- a/src/share/classes/java/nio/channels/AsynchronousServerSocketChannel.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/java/nio/channels/AsynchronousServerSocketChannel.java	Sun Aug 23 12:53:45 2009 +0100
@@ -85,9 +85,6 @@
  *      public void failed(Throwable exc, Void att) {
  *          ...
  *      }
- *      public void cancelled(Void att) {
- *          ...
- *      }
  *  });
  * </pre>
  *
@@ -240,11 +237,11 @@
     /**
      * Accepts a connection.
      *
-     * <p> This method initiates accepting a connection made to this channel's
-     * socket, returning a {@link Future} representing the pending result
-     * of the operation. The {@code Future}'s {@link Future#get() get}
-     * method will return the {@link AsynchronousSocketChannel} for the new
-     * connection on successful completion.
+     * <p> This method initiates an asynchronous operation to accept a
+     * connection made to this channel's socket. The {@code handler} parameter is
+     * a completion handler that is invoked when a connection is accepted (or
+     * the operation fails). The result passed to the completion handler is
+     * the {@link AsynchronousSocketChannel} to the new connection.
      *
      * <p> When a new connection is accepted then the resulting {@code
      * AsynchronousSocketChannel} will be bound to the same {@link
@@ -269,35 +266,35 @@
      * @param   attachment
      *          The object to attach to the I/O operation; can be {@code null}
      * @param   handler
-     *          The handler for consuming the result; can be {@code null}
-     *
-     * @return  an <tt>Future</tt> object representing the pending result
+     *          The handler for consuming the result
      *
      * @throws  AcceptPendingException
      *          If an accept operation is already in progress on this channel
      * @throws  NotYetBoundException
      *          If this channel's socket has not yet been bound
      * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
+     *          If the channel group has terminated
      */
-    public abstract <A> Future<AsynchronousSocketChannel>
-        accept(A attachment, CompletionHandler<AsynchronousSocketChannel,? super A> handler);
+    public abstract <A> void accept(A attachment,
+                                    CompletionHandler<AsynchronousSocketChannel,? super A> handler);
 
     /**
      * Accepts a connection.
      *
-     * <p> This method is equivalent to invoking {@link
-     * #accept(Object,CompletionHandler)} with the {@code attachment}
-     * and {@code handler} parameters set to {@code null}.
+     * <p> This method initiates an asynchronous operation to accept a
+     * connection made to this channel's socket. The method behaves in exactly
+     * the same manner as the {@link #accept(Object, CompletionHandler)} method
+     * except that instead of specifying a completion handler, this method
+     * returns a {@code Future} representing the pending result. The {@code
+     * Future}'s {@link Future#get() get} method returns the {@link
+     * AsynchronousSocketChannel} to the new connection on successful completion.
      *
-     * @return  an <tt>Future</tt> object representing the pending result
+     * @return  a {@code Future} object representing the pending result
      *
      * @throws  AcceptPendingException
      *          If an accept operation is already in progress on this channel
      * @throws  NotYetBoundException
      *          If this channel's socket has not yet been bound
      */
-    public final Future<AsynchronousSocketChannel> accept() {
-        return accept(null, null);
-    }
+    public abstract Future<AsynchronousSocketChannel> accept();
 }
--- a/src/share/classes/java/nio/channels/AsynchronousSocketChannel.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/java/nio/channels/AsynchronousSocketChannel.java	Sun Aug 23 12:53:45 2009 +0100
@@ -274,14 +274,11 @@
     /**
      * Connects this channel.
      *
-     * <p> This method initiates an operation to connect this channel, returning
-     * a {@code Future} representing the pending result of the operation. If
-     * the connection is successfully established then the {@code Future}'s
-     * {@link Future#get() get} method will return {@code null}. If the
-     * connection cannot be established then the channel is closed. In that case,
-     * invoking the {@code get} method throws {@link
-     * java.util.concurrent.ExecutionException} with an {@code IOException} as
-     * the cause.
+     * <p> This method initiates an operation to connect this channel. The
+     * {@code handler} parameter is a completion handler that is invoked when
+     * the connection is successfully established or connection cannot be
+     * established. If the connection cannot be established then the channel is
+     * closed.
      *
      * <p> This method performs exactly the same security checks as the {@link
      * java.net.Socket} class.  That is, if a security manager has been
@@ -294,9 +291,7 @@
      * @param   attachment
      *          The object to attach to the I/O operation; can be {@code null}
      * @param   handler
-     *          The handler for consuming the result; can be {@code null}
-     *
-     * @return  A {@code Future} object representing the pending result
+     *          The handler for consuming the result
      *
      * @throws  UnresolvedAddressException
      *          If the given remote address is not fully resolved
@@ -307,23 +302,26 @@
      * @throws  ConnectionPendingException
      *          If a connection operation is already in progress on this channel
      * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
+     *          If the channel group has terminated
      * @throws  SecurityException
      *          If a security manager has been installed
      *          and it does not permit access to the given remote endpoint
      *
      * @see #getRemoteAddress
      */
-    public abstract <A> Future<Void> connect(SocketAddress remote,
-                                             A attachment,
-                                             CompletionHandler<Void,? super A> handler);
+    public abstract <A> void connect(SocketAddress remote,
+                                     A attachment,
+                                     CompletionHandler<Void,? super A> handler);
 
     /**
      * Connects this channel.
      *
-     * <p> This method is equivalent to invoking {@link
-     * #connect(SocketAddress,Object,CompletionHandler)} with the {@code attachment}
-     * and handler parameters set to {@code null}.
+     * <p> This method initiates an operation to connect this channel. This
+     * method behaves in exactly the same manner as the {@link
+     * #connect(SocketAddress, Object, CompletionHandler)} method except that
+     * instead of specifying a completion handler, this method returns a {@code
+     * Future} representing the pending result. The {@code Future}'s {@link
+     * Future#get() get} method returns {@code null} on successful completion.
      *
      * @param   remote
      *          The remote address to which this channel is to be connected
@@ -342,18 +340,17 @@
      *          If a security manager has been installed
      *          and it does not permit access to the given remote endpoint
      */
-    public final Future<Void> connect(SocketAddress remote) {
-        return connect(remote, null, null);
-    }
+    public abstract Future<Void> connect(SocketAddress remote);
 
     /**
      * Reads a sequence of bytes from this channel into the given buffer.
      *
-     * <p> This method initiates the reading of a sequence of bytes from this
-     * channel into the given buffer, returning a {@code Future} representing
-     * the pending result of the operation. The {@code Future}'s {@link
-     * Future#get() get} method returns the number of bytes read or {@code -1}
-     * if all bytes have been read and channel has reached end-of-stream.
+     * <p> This method initiates an asynchronous read operation to read a
+     * sequence of bytes from this channel into the given buffer. The {@code
+     * handler} parameter is a completion handler that is invoked when the read
+     * operation completes (or fails). The result passed to the completion
+     * handler is the number of bytes read or {@code -1} if no bytes could be
+     * read because the channel has reached end-of-stream.
      *
      * <p> If a timeout is specified and the timeout elapses before the operation
      * completes then the operation completes with the exception {@link
@@ -376,9 +373,7 @@
      * @param   attachment
      *          The object to attach to the I/O operation; can be {@code null}
      * @param   handler
-     *          The handler for consuming the result; can be {@code null}
-     *
-     * @return  A {@code Future} object representing the pending result
+     *          The handler for consuming the result
      *
      * @throws  IllegalArgumentException
      *          If the {@code timeout} parameter is negative or the buffer is
@@ -388,13 +383,13 @@
      * @throws  NotYetConnectedException
      *          If this channel is not yet connected
      * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
+     *          If the channel group has terminated
      */
-    public abstract <A> Future<Integer> read(ByteBuffer dst,
-                                             long timeout,
-                                             TimeUnit unit,
-                                             A attachment,
-                                             CompletionHandler<Integer,? super A> handler);
+    public abstract <A> void read(ByteBuffer dst,
+                                  long timeout,
+                                  TimeUnit unit,
+                                  A attachment,
+                                  CompletionHandler<Integer,? super A> handler);
 
     /**
      * @throws  IllegalArgumentException        {@inheritDoc}
@@ -402,14 +397,14 @@
      * @throws  NotYetConnectedException
      *          If this channel is not yet connected
      * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
+     *          If the channel group has terminated
      */
     @Override
-    public final <A> Future<Integer> read(ByteBuffer dst,
-                                          A attachment,
-                                          CompletionHandler<Integer,? super A> handler)
+    public final <A> void read(ByteBuffer dst,
+                               A attachment,
+                               CompletionHandler<Integer,? super A> handler)
     {
-        return read(dst, 0L, TimeUnit.MILLISECONDS, attachment, handler);
+        read(dst, 0L, TimeUnit.MILLISECONDS, attachment, handler);
     }
 
     /**
@@ -419,16 +414,18 @@
      *          If this channel is not yet connected
      */
     @Override
-    public final Future<Integer> read(ByteBuffer dst) {
-        return read(dst, 0L, TimeUnit.MILLISECONDS, null, null);
-    }
+    public abstract Future<Integer> read(ByteBuffer dst);
 
     /**
      * Reads a sequence of bytes from this channel into a subsequence of the
      * given buffers. This operation, sometimes called a <em>scattering read</em>,
      * is often useful when implementing network protocols that group data into
      * segments consisting of one or more fixed-length headers followed by a
-     * variable-length body.
+     * variable-length body. The {@code handler} parameter is a completion
+     * handler that is invoked when the read operation completes (or fails). The
+     * result passed to the completion handler is the number of bytes read or
+     * {@code -1} if no bytes could be read because the channel has reached
+     * end-of-stream.
      *
      * <p> This method initiates a read of up to <i>r</i> bytes from this channel,
      * where <i>r</i> is the total number of bytes remaining in the specified
@@ -456,11 +453,6 @@
      * I/O operation is performed with the maximum number of buffers allowed by
      * the operating system.
      *
-     * <p> The return value from this method is a {@code Future} representing
-     * the pending result of the operation. The {@code Future}'s {@link
-     * Future#get() get} method returns the number of bytes read or {@code -1L}
-     * if all bytes have been read and the channel has reached end-of-stream.
-     *
      * <p> If a timeout is specified and the timeout elapses before the operation
      * completes then it completes with the exception {@link
      * InterruptedByTimeoutException}. Where a timeout occurs, and the
@@ -485,9 +477,7 @@
      * @param   attachment
      *          The object to attach to the I/O operation; can be {@code null}
      * @param   handler
-     *          The handler for consuming the result; can be {@code null}
-     *
-     * @return  A {@code Future} object representing the pending result
+     *          The handler for consuming the result
      *
      * @throws  IndexOutOfBoundsException
      *          If the pre-conditions for the {@code offset}  and {@code length}
@@ -500,23 +490,24 @@
      * @throws  NotYetConnectedException
      *          If this channel is not yet connected
      * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
+     *          If the channel group has terminated
      */
-    public abstract <A> Future<Long> read(ByteBuffer[] dsts,
-                                          int offset,
-                                          int length,
-                                          long timeout,
-                                          TimeUnit unit,
-                                          A attachment,
-                                          CompletionHandler<Long,? super A> handler);
+    public abstract <A> void read(ByteBuffer[] dsts,
+                                  int offset,
+                                  int length,
+                                  long timeout,
+                                  TimeUnit unit,
+                                  A attachment,
+                                  CompletionHandler<Long,? super A> handler);
 
     /**
      * Writes a sequence of bytes to this channel from the given buffer.
      *
-     * <p> This method initiates the writing of a sequence of bytes to this channel
-     * from the given buffer, returning a {@code Future} representing the
-     * pending result of the operation. The {@code Future}'s {@link Future#get()
-     * get} method will return the number of bytes written.
+     * <p> This method initiates an asynchronous write operation to write a
+     * sequence of bytes to this channel from the given buffer. The {@code
+     * handler} parameter is a completion handler that is invoked when the write
+     * operation completes (or fails). The result passed to the completion
+     * handler is the number of bytes written.
      *
      * <p> If a timeout is specified and the timeout elapses before the operation
      * completes then it completes with the exception {@link
@@ -539,9 +530,7 @@
      * @param   attachment
      *          The object to attach to the I/O operation; can be {@code null}
      * @param   handler
-     *          The handler for consuming the result; can be {@code null}
-     *
-     * @return  A {@code Future} object representing the pending result
+     *          The handler for consuming the result
      *
      * @throws  IllegalArgumentException
      *          If the {@code timeout} parameter is negative
@@ -550,28 +539,28 @@
      * @throws  NotYetConnectedException
      *          If this channel is not yet connected
      * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
+     *          If the channel group has terminated
      */
-    public abstract <A> Future<Integer> write(ByteBuffer src,
-                                              long timeout,
-                                              TimeUnit unit,
-                                              A attachment,
-                                              CompletionHandler<Integer,? super A> handler);
+    public abstract <A> void write(ByteBuffer src,
+                                   long timeout,
+                                   TimeUnit unit,
+                                   A attachment,
+                                   CompletionHandler<Integer,? super A> handler);
 
     /**
      * @throws  WritePendingException          {@inheritDoc}
      * @throws  NotYetConnectedException
      *          If this channel is not yet connected
      * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
+     *          If the channel group has terminated
      */
     @Override
-    public final <A> Future<Integer> write(ByteBuffer src,
-                                           A attachment,
-                                           CompletionHandler<Integer,? super A> handler)
+    public final <A> void write(ByteBuffer src,
+                                A attachment,
+                                CompletionHandler<Integer,? super A> handler)
 
     {
-        return write(src, 0L, TimeUnit.MILLISECONDS, attachment, handler);
+        write(src, 0L, TimeUnit.MILLISECONDS, attachment, handler);
     }
 
     /**
@@ -580,16 +569,16 @@
      *          If this channel is not yet connected
      */
     @Override
-    public final Future<Integer> write(ByteBuffer src) {
-        return write(src, 0L, TimeUnit.MILLISECONDS, null, null);
-    }
+    public abstract Future<Integer> write(ByteBuffer src);
 
     /**
      * Writes a sequence of bytes to this channel from a subsequence of the given
      * buffers. This operation, sometimes called a <em>gathering write</em>, is
      * often useful when implementing network protocols that group data into
      * segments consisting of one or more fixed-length headers followed by a
-     * variable-length body.
+     * variable-length body. The {@code handler} parameter is a completion
+     * handler that is invoked when the write operation completes (or fails).
+     * The result passed to the completion handler is the number of bytes written.
      *
      * <p> This method initiates a write of up to <i>r</i> bytes to this channel,
      * where <i>r</i> is the total number of bytes remaining in the specified
@@ -616,10 +605,6 @@
      * remaining), exceeds this limit, then the I/O operation is performed with
      * the maximum number of buffers allowed by the operating system.
      *
-     * <p> The return value from this method is a {@code Future} representing
-     * the pending result of the operation. The {@code Future}'s {@link
-     * Future#get() get} method will return the number of bytes written.
-     *
      * <p> If a timeout is specified and the timeout elapses before the operation
      * completes then it completes with the exception {@link
      * InterruptedByTimeoutException}. Where a timeout occurs, and the
@@ -644,9 +629,7 @@
      * @param   attachment
      *          The object to attach to the I/O operation; can be {@code null}
      * @param   handler
-     *          The handler for consuming the result; can be {@code null}
-     *
-     * @return  A {@code Future} object representing the pending result
+     *          The handler for consuming the result
      *
      * @throws  IndexOutOfBoundsException
      *          If the pre-conditions for the {@code offset}  and {@code length}
@@ -658,13 +641,13 @@
      * @throws  NotYetConnectedException
      *          If this channel is not yet connected
      * @throws  ShutdownChannelGroupException
-     *          If a handler is specified, and the channel group is shutdown
+     *          If the channel group has terminated
      */
-    public abstract <A> Future<Long> write(ByteBuffer[] srcs,
-                                           int offset,
-                                           int length,
-                                           long timeout,
-                                           TimeUnit unit,
-                                           A attachment,
-                                           CompletionHandler<Long,? super A> handler);
+    public abstract <A> void write(ByteBuffer[] srcs,
+                                   int offset,
+                                   int length,
+                                   long timeout,
+                                   TimeUnit unit,
+                                   A attachment,
+                                   CompletionHandler<Long,? super A> handler);
 }
--- a/src/share/classes/java/nio/channels/CompletionHandler.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/java/nio/channels/CompletionHandler.java	Sun Aug 23 12:53:45 2009 +0100
@@ -32,11 +32,9 @@
  * handler to be specified to consume the result of an asynchronous operation.
  * The {@link #completed completed} method is invoked when the I/O operation
  * completes successfully. The {@link #failed failed} method is invoked if the
- * I/O operations fails. The {@link #cancelled cancelled} method is invoked when
- * the I/O operation is cancelled by invoking the {@link
- * java.util.concurrent.Future#cancel cancel} method. The implementations of
- * these methods should complete in a timely manner so as to avoid keeping the
- * invoking thread from dispatching to other completion handlers.
+ * I/O operations fails. The implementations of these methods should complete
+ * in a timely manner so as to avoid keeping the invoking thread from dispatching
+ * to other completion handlers.
  *
  * @param   <V>     The result type of the I/O operation
  * @param   <A>     The type of the object attached to the I/O operation
@@ -65,13 +63,4 @@
      *          The object attached to the I/O operation when it was initiated.
      */
     void failed(Throwable exc, A attachment);
-
-    /**
-     * Invoked when an operation is cancelled by invoking the {@link
-     * java.util.concurrent.Future#cancel cancel} method.
-     *
-     * @param   attachment
-     *          The object attached to the I/O operation when it was initiated.
-     */
-    void cancelled(A attachment);
 }
--- a/src/share/classes/java/nio/channels/exceptions	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/java/nio/channels/exceptions	Sun Aug 23 12:53:45 2009 +0100
@@ -190,5 +190,5 @@
 gen ShutdownChannelGroupException "
  * Unchecked exception thrown when an attempt is made to construct a channel in 
  * a group that is shutdown or the completion handler for an I/O operation 
- * cannot be invoked because the channel group is shutdown." \
+ * cannot be invoked because the channel group has terminated." \
  -3903801676350154157L
--- a/src/share/classes/sun/nio/ch/AbstractFuture.java	Sat Aug 22 17:40:18 2009 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,63 +0,0 @@
-/*
- * Copyright 2008-2009 Sun Microsystems, Inc.  All Rights Reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.  Sun designates this
- * particular file as subject to the "Classpath" exception as provided
- * by Sun in the LICENSE file that accompanied this code.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
- */
-
-package sun.nio.ch;
-
-import java.nio.channels.AsynchronousChannel;
-import java.util.concurrent.Future;
-
-/**
- * Base implementation of Future used for asynchronous I/O
- */
-
-abstract class AbstractFuture<V,A>
-    implements Future<V>
-{
-    private final AsynchronousChannel channel;
-    private final A attachment;
-
-    protected AbstractFuture(AsynchronousChannel channel, A attachment) {
-        this.channel = channel;
-        this.attachment = attachment;
-    }
-
-    final AsynchronousChannel channel() {
-        return channel;
-    }
-
-    final A attachment() {
-        return attachment;
-    }
-
-    /**
-     * Returns the result of the operation if it has completed successfully.
-     */
-    abstract V value();
-
-    /**
-     * Returns the exception if the operation has failed.
-     */
-    abstract Throwable exception();
-}
--- a/src/share/classes/sun/nio/ch/AsynchronousChannelGroupImpl.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/sun/nio/ch/AsynchronousChannelGroupImpl.java	Sun Aug 23 12:53:45 2009 +0100
@@ -32,8 +32,8 @@
 import java.io.FileDescriptor;
 import java.util.Queue;
 import java.util.concurrent.*;
-import java.util.concurrent.locks.*;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.security.PrivilegedAction;
 import java.security.AccessController;
 import java.security.AccessControlContext;
@@ -65,11 +65,8 @@
     private final Queue<Runnable> taskQueue;
 
     // group shutdown
-    // shutdownLock is RW lock so as to allow for concurrent queuing of tasks
-    // when using a fixed thread pool.
-    private final ReadWriteLock shutdownLock = new ReentrantReadWriteLock();
+    private final AtomicBoolean shutdown = new AtomicBoolean();
     private final Object shutdownNowLock = new Object();
-    private volatile boolean shutdown;
     private volatile boolean terminateInitiated;
 
     AsynchronousChannelGroupImpl(AsynchronousChannelProvider provider,
@@ -214,7 +211,7 @@
 
     @Override
     public final boolean isShutdown() {
-        return shutdown;
+        return shutdown.get();
     }
 
     @Override
@@ -260,17 +257,10 @@
 
     @Override
     public final void shutdown() {
-        shutdownLock.writeLock().lock();
-        try {
-            if (shutdown) {
-                // already shutdown
-                return;
-            }
-            shutdown = true;
-        } finally {
-            shutdownLock.writeLock().unlock();
+        if (shutdown.getAndSet(true)) {
+            // already shutdown
+            return;
         }
-
         // if there are channels in the group then shutdown will continue
         // when the last channel is closed
         if (!isEmpty()) {
@@ -289,12 +279,7 @@
 
     @Override
     public final void shutdownNow() throws IOException {
-        shutdownLock.writeLock().lock();
-        try {
-            shutdown = true;
-        } finally {
-            shutdownLock.writeLock().unlock();
-        }
+        shutdown.set(true);
         synchronized (shutdownNowLock) {
             if (!terminateInitiated) {
                 terminateInitiated = true;
@@ -305,6 +290,18 @@
         }
     }
 
+    /**
+     * For use by AsynchronousFileChannel to release resources without shutting
+     * down the thread pool.
+     */
+    final void detachFromThreadPool() {
+        if (shutdown.getAndSet(true))
+            throw new AssertionError("Already shutdown");
+        if (!isEmpty())
+            throw new AssertionError("Group not empty");
+        shutdownHandlerTasks();
+    }
+
     @Override
     public final boolean awaitTermination(long timeout, TimeUnit unit)
         throws InterruptedException
--- a/src/share/classes/sun/nio/ch/AsynchronousFileChannelImpl.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/sun/nio/ch/AsynchronousFileChannelImpl.java	Sun Aug 23 12:53:45 2009 +0100
@@ -25,8 +25,10 @@
 
 package sun.nio.ch;
 
+import java.nio.ByteBuffer;
 import java.nio.channels.*;
 import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Future;
 import java.util.concurrent.locks.*;
 import java.io.FileDescriptor;
 import java.io.IOException;
@@ -101,6 +103,33 @@
 
     // -- file locking --
 
+    abstract <A> Future<FileLock> implLock(long position,
+                                           long size,
+                                           boolean shared,
+                                           A attachment,
+                                           CompletionHandler<FileLock,? super A> handler);
+
+    @Override
+    public final Future<FileLock> lock(long position,
+                                       long size,
+                                       boolean shared)
+
+    {
+        return implLock(position, size, shared, null, null);
+    }
+
+    @Override
+    public final <A> void lock(long position,
+                               long size,
+                               boolean shared,
+                               A attachment,
+                               CompletionHandler<FileLock,? super A> handler)
+    {
+        if (handler == null)
+            throw new NullPointerException("'handler' is null");
+        implLock(position, size, shared, attachment, handler);
+    }
+
     private volatile FileLockTable fileLockTable;
 
     final void ensureFileLockTableInitialized() throws IOException {
@@ -175,4 +204,50 @@
             end();
         }
     }
+
+
+    // -- reading and writing --
+
+    abstract <A> Future<Integer> implRead(ByteBuffer dst,
+                                         long position,
+                                         A attachment,
+                                         CompletionHandler<Integer,? super A> handler);
+
+    @Override
+    public final Future<Integer> read(ByteBuffer dst, long position) {
+        return implRead(dst, position, null, null);
+    }
+
+    @Override
+    public final <A> void read(ByteBuffer dst,
+                               long position,
+                               A attachment,
+                               CompletionHandler<Integer,? super A> handler)
+    {
+        if (handler == null)
+            throw new NullPointerException("'handler' is null");
+        implRead(dst, position, attachment, handler);
+    }
+
+    abstract <A> Future<Integer> implWrite(ByteBuffer src,
+                                           long position,
+                                           A attachment,
+                                           CompletionHandler<Integer,? super A> handler);
+
+
+    @Override
+    public final Future<Integer> write(ByteBuffer src, long position) {
+        return implWrite(src, position, null, null);
+    }
+
+    @Override
+    public final <A> void write(ByteBuffer src,
+                                long position,
+                                A attachment,
+                                CompletionHandler<Integer,? super A> handler)
+    {
+        if (handler == null)
+            throw new NullPointerException("'handler' is null");
+        implWrite(src, position, attachment, handler);
+    }
 }
--- a/src/share/classes/sun/nio/ch/AsynchronousServerSocketChannelImpl.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/sun/nio/ch/AsynchronousServerSocketChannelImpl.java	Sun Aug 23 12:53:45 2009 +0100
@@ -35,6 +35,7 @@
 import java.util.Set;
 import java.util.HashSet;
 import java.util.Collections;
+import java.util.concurrent.Future;
 import java.util.concurrent.locks.ReadWriteLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 import sun.net.NetHooks;
@@ -108,6 +109,29 @@
         implClose();
     }
 
+    /**
+     * Invoked by accept to accept connection
+     */
+    abstract Future<AsynchronousSocketChannel>
+        implAccept(Object attachment,
+                   CompletionHandler<AsynchronousSocketChannel,Object> handler);
+
+
+    @Override
+    public final Future<AsynchronousSocketChannel> accept() {
+        return implAccept(null, null);
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public final <A> void accept(A attachment,
+                                 CompletionHandler<AsynchronousSocketChannel,? super A> handler)
+    {
+        if (handler == null)
+            throw new NullPointerException("'handler' is null");
+        implAccept(attachment, (CompletionHandler<AsynchronousSocketChannel,Object>)handler);
+    }
+
     final boolean isAcceptKilled() {
         return acceptKilled;
     }
--- a/src/share/classes/sun/nio/ch/AsynchronousSocketChannelImpl.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/sun/nio/ch/AsynchronousSocketChannelImpl.java	Sun Aug 23 12:53:45 2009 +0100
@@ -184,28 +184,53 @@
     }
 
     /**
+     * Invoked by connect to initiate the connect operation.
+     */
+    abstract <A> Future<Void> implConnect(SocketAddress remote,
+                                          A attachment,
+                                          CompletionHandler<Void,? super A> handler);
+
+    @Override
+    public final Future<Void> connect(SocketAddress remote) {
+        return implConnect(remote, null, null);
+    }
+
+    @Override
+    public final <A> void connect(SocketAddress remote,
+                                  A attachment,
+                                  CompletionHandler<Void,? super A> handler)
+    {
+        if (handler == null)
+            throw new NullPointerException("'handler' is null");
+        implConnect(remote, attachment, handler);
+    }
+
+    /**
      * Invoked by read to initiate the I/O operation.
      */
-    abstract <V extends Number,A> Future<V> readImpl(ByteBuffer[] dsts,
-                                                     boolean isScatteringRead,
+    abstract <V extends Number,A> Future<V> implRead(boolean isScatteringRead,
+                                                     ByteBuffer dst,
+                                                     ByteBuffer[] dsts,
                                                      long timeout,
                                                      TimeUnit unit,
                                                      A attachment,
                                                      CompletionHandler<V,? super A> handler);
 
     @SuppressWarnings("unchecked")
-    private <V extends Number,A> Future<V> read(ByteBuffer[] dsts,
-                                                boolean isScatteringRead,
+    private <V extends Number,A> Future<V> read(boolean isScatteringRead,
+                                                ByteBuffer dst,
+                                                ByteBuffer[] dsts,
                                                 long timeout,
                                                 TimeUnit unit,
-                                                A attachment,
+                                                A att,
                                                 CompletionHandler<V,? super A> handler)
     {
         if (!isOpen()) {
-            CompletedFuture<V,A> result = CompletedFuture
-                .withFailure(this, new ClosedChannelException(), attachment);
-            Invoker.invoke(handler, result);
-            return result;
+            Throwable e = new ClosedChannelException();
+            if (handler == null)
+                return CompletedFuture.withFailure(e);
+            Invoker.invoke(this, handler, att, null, e);
+            return null;
         }
 
         if (remoteAddress == null)
@@ -213,13 +238,13 @@
         if (timeout < 0L)
             throw new IllegalArgumentException("Negative timeout");
 
-        boolean hasSpaceToRead = isScatteringRead || dsts[0].hasRemaining();
+        boolean hasSpaceToRead = isScatteringRead || dst.hasRemaining();
         boolean shutdown = false;
 
         // check and update state
         synchronized (readLock) {
             if (readKilled)
-                throw new RuntimeException("Reading not allowed due to timeout or cancellation");
+                throw new IllegalStateException("Reading not allowed due to timeout or cancellation");
             if (reading)
                 throw new ReadPendingException();
             if (readShutdown) {
@@ -234,44 +259,53 @@
         // immediately complete with -1 if shutdown for read
         // immediately complete with 0 if no space remaining
         if (shutdown || !hasSpaceToRead) {
-            CompletedFuture<V,A> result;
+            Number result;
             if (isScatteringRead) {
-                Long value = (shutdown) ? Long.valueOf(-1L) : Long.valueOf(0L);
-                result = (CompletedFuture<V,A>)CompletedFuture.withResult(this, value, attachment);
+                result = (shutdown) ? Long.valueOf(-1L) : Long.valueOf(0L);
             } else {
-                int value = (shutdown) ? -1 : 0;
-                result = (CompletedFuture<V,A>)CompletedFuture.withResult(this, value, attachment);
+                result = (shutdown) ? -1 : 0;
             }
-            Invoker.invoke(handler, result);
-            return result;
+            if (handler == null)
+                return CompletedFuture.withResult((V)result);
+            Invoker.invoke(this, handler, att, (V)result, null);
+            return null;
         }
 
-        return readImpl(dsts, isScatteringRead, timeout, unit, attachment, handler);
+        return implRead(isScatteringRead, dst, dsts, timeout, unit, att, handler);
     }
 
     @Override
-    public final <A> Future<Integer> read(ByteBuffer dst,
-                                          long timeout,
-                                          TimeUnit unit,
-                                          A attachment,
-                                          CompletionHandler<Integer,? super A> handler)
-    {
+    public final Future<Integer> read(ByteBuffer dst) {
         if (dst.isReadOnly())
             throw new IllegalArgumentException("Read-only buffer");
-        ByteBuffer[] bufs = new ByteBuffer[1];
-        bufs[0] = dst;
-        return read(bufs, false, timeout, unit, attachment, handler);
+        return read(false, dst, null, 0L, TimeUnit.MILLISECONDS, null, null);
     }
 
     @Override
-    public final <A> Future<Long> read(ByteBuffer[] dsts,
-                                       int offset,
-                                       int length,
-                                       long timeout,
-                                       TimeUnit unit,
-                                       A attachment,
-                                       CompletionHandler<Long,? super A> handler)
+    public final <A> void read(ByteBuffer dst,
+                               long timeout,
+                               TimeUnit unit,
+                               A attachment,
+                               CompletionHandler<Integer,? super A> handler)
     {
+        if (handler == null)
+            throw new NullPointerException("'handler' is null");
+        if (dst.isReadOnly())
+            throw new IllegalArgumentException("Read-only buffer");
+        read(false, dst, null, timeout, unit, attachment, handler);
+    }
+
+    @Override
+    public final <A> void read(ByteBuffer[] dsts,
+                               int offset,
+                               int length,
+                               long timeout,
+                               TimeUnit unit,
+                               A attachment,
+                               CompletionHandler<Long,? super A> handler)
+    {
+        if (handler == null)
+            throw new NullPointerException("'handler' is null");
         if ((offset < 0) || (length < 0) || (offset > dsts.length - length))
             throw new IndexOutOfBoundsException();
         ByteBuffer[] bufs = Util.subsequence(dsts, offset, length);
@@ -279,39 +313,41 @@
             if (bufs[i].isReadOnly())
                 throw new IllegalArgumentException("Read-only buffer");
         }
-        return read(bufs, true, timeout, unit, attachment, handler);
+        read(true, null, bufs, timeout, unit, attachment, handler);
     }
 
     /**
      * Invoked by write to initiate the I/O operation.
      */
-    abstract <V extends Number,A> Future<V> writeImpl(ByteBuffer[] srcs,
-                                                      boolean isGatheringWrite,
+    abstract <V extends Number,A> Future<V> implWrite(boolean isGatheringWrite,
+                                                      ByteBuffer src,
+                                                      ByteBuffer[] srcs,
                                                       long timeout,
                                                       TimeUnit unit,
                                                       A attachment,
                                                       CompletionHandler<V,? super A> handler);
 
     @SuppressWarnings("unchecked")
-    private <V extends Number,A> Future<V> write(ByteBuffer[] srcs,
-                                                 boolean isGatheringWrite,
+    private <V extends Number,A> Future<V> write(boolean isGatheringWrite,
+                                                 ByteBuffer src,
+                                                 ByteBuffer[] srcs,
                                                  long timeout,
                                                  TimeUnit unit,
-                                                 A attachment,
+                                                 A att,
                                                  CompletionHandler<V,? super A> handler)
     {
-        boolean hasDataToWrite = isGatheringWrite || srcs[0].hasRemaining();
+        boolean hasDataToWrite = isGatheringWrite || src.hasRemaining();
 
         boolean closed = false;
         if (isOpen()) {
             if (remoteAddress == null)
                 throw new NotYetConnectedException();
-            if (timeout < 0L)
+             if (timeout < 0L)
                 throw new IllegalArgumentException("Negative timeout");
             // check and update state
             synchronized (writeLock) {
                 if (writeKilled)
-                    throw new RuntimeException("Writing not allowed due to timeout or cancellation");
+                    throw new IllegalStateException("Writing not allowed due to timeout or cancellation");
                 if (writing)
                     throw new WritePendingException();
                 if (writeShutdown) {
@@ -327,52 +363,57 @@
 
         // channel is closed or shutdown for write
         if (closed) {
-            CompletedFuture<V,A> result = CompletedFuture
-                .withFailure(this, new ClosedChannelException(), attachment);
-            Invoker.invoke(handler, result);
-            return result;
+            Throwable e = new ClosedChannelException();
+            if (handler == null)
+                return CompletedFuture.withFailure(e);
+            Invoker.invoke(this, handler, att, null, e);
+            return null;
         }
 
         // nothing to write so complete immediately
         if (!hasDataToWrite) {
-            CompletedFuture<V,A> result;
-            if (isGatheringWrite) {
-                result = (CompletedFuture<V,A>)CompletedFuture.withResult(this, 0L, attachment);
-            } else {
-                result = (CompletedFuture<V,A>)CompletedFuture.withResult(this, 0, attachment);
-            }
-            Invoker.invoke(handler, result);
-            return result;
+            Number result = (isGatheringWrite) ? (Number)0L : (Number)0;
+            if (handler == null)
+                return CompletedFuture.withResult((V)result);
+            Invoker.invoke(this, handler, att, (V)result, null);
+            return null;
         }
 
-        return writeImpl(srcs, isGatheringWrite, timeout, unit, attachment, handler);
+        return implWrite(isGatheringWrite, src, srcs, timeout, unit, att, handler);
     }
 
     @Override
-    public final <A> Future<Integer> write(ByteBuffer src,
-                                           long timeout,
-                                           TimeUnit unit,
-                                           A attachment,
-                                           CompletionHandler<Integer,? super A> handler)
-    {
-        ByteBuffer[] bufs = new ByteBuffer[1];
-        bufs[0] = src;
-        return write(bufs, false, timeout, unit, attachment, handler);
+    public final Future<Integer> write(ByteBuffer src) {
+        return write(false, src, null, 0L, TimeUnit.MILLISECONDS, null, null);
     }
 
     @Override
-    public final <A> Future<Long> write(ByteBuffer[] srcs,
-                                        int offset,
-                                        int length,
-                                        long timeout,
-                                        TimeUnit unit,
-                                        A attachment,
-                                        CompletionHandler<Long,? super A> handler)
+    public final <A> void write(ByteBuffer src,
+                                long timeout,
+                                TimeUnit unit,
+                                A attachment,
+                                CompletionHandler<Integer,? super A> handler)
     {
+        if (handler == null)
+            throw new NullPointerException("'handler' is null");
+        write(false, src, null, timeout, unit, attachment, handler);
+    }
+
+    @Override
+    public final <A> void  write(ByteBuffer[] srcs,
+                                 int offset,
+                                 int length,
+                                 long timeout,
+                                 TimeUnit unit,
+                                 A attachment,
+                                 CompletionHandler<Long,? super A> handler)
+    {
+        if (handler == null)
+            throw new NullPointerException("'handler' is null");
         if ((offset < 0) || (length < 0) || (offset > srcs.length - length))
             throw new IndexOutOfBoundsException();
         srcs = Util.subsequence(srcs, offset, length);
-        return write(srcs, true, timeout, unit, attachment, handler);
+        write(true, null, srcs, timeout, unit, attachment, handler);
     }
 
     @Override
@@ -461,7 +502,6 @@
     }
 
     @Override
-    @SuppressWarnings("unchecked")
     public final SocketAddress getRemoteAddress() throws IOException {
         if (!isOpen())
             throw new ClosedChannelException();
--- a/src/share/classes/sun/nio/ch/CompletedFuture.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/sun/nio/ch/CompletedFuture.java	Sun Aug 23 12:53:45 2009 +0100
@@ -25,7 +25,7 @@
 
 package sun.nio.ch;
 
-import java.nio.channels.AsynchronousChannel;
+import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.ExecutionException;
 import java.io.IOException;
@@ -35,39 +35,35 @@
  * completed.
  */
 
-final class CompletedFuture<V,A>
-    extends AbstractFuture<V,A>
-{
+final class CompletedFuture<V> implements Future<V> {
     private final V result;
     private final Throwable exc;
 
-    private CompletedFuture(AsynchronousChannel channel,
-                            V result,
-                            Throwable exc,
-                            A attachment)
-    {
-        super(channel, attachment);
+    private CompletedFuture(V result, Throwable exc) {
         this.result = result;
         this.exc = exc;
     }
 
     @SuppressWarnings("unchecked")
-    static <V,A> CompletedFuture<V,A> withResult(AsynchronousChannel channel,
-                                                 V result,
-                                                 A attachment)
-    {
-        return new CompletedFuture<V,A>(channel, result, null, attachment);
+    static <V> CompletedFuture<V> withResult(V result) {
+        return new CompletedFuture<V>(result, null);
     }
 
     @SuppressWarnings("unchecked")
-    static <V,A> CompletedFuture<V,A> withFailure(AsynchronousChannel channel,
-                                                  Throwable exc,
-                                                  A attachment)
-    {
+    static <V> CompletedFuture<V> withFailure(Throwable exc) {
         // exception must be IOException or SecurityException
         if (!(exc instanceof IOException) && !(exc instanceof SecurityException))
             exc = new IOException(exc);
-        return new CompletedFuture(channel, null, exc, attachment);
+        return new CompletedFuture(null, exc);
+    }
+
+    @SuppressWarnings("unchecked")
+    static <V> CompletedFuture<V> withResult(V result, Throwable exc) {
+        if (exc == null) {
+            return withResult(result);
+        } else {
+            return withFailure(exc);
+        }
     }
 
     @Override
@@ -100,14 +96,4 @@
     public boolean cancel(boolean mayInterruptIfRunning) {
         return false;
     }
-
-    @Override
-    Throwable exception() {
-        return exc;
-    }
-
-    @Override
-    V value() {
-        return result;
-    }
 }
--- a/src/share/classes/sun/nio/ch/Invoker.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/sun/nio/ch/Invoker.java	Sun Aug 23 12:53:45 2009 +0100
@@ -117,33 +117,32 @@
      * Invoke handler without checking the thread identity or number of handlers
      * on the thread stack.
      */
-    @SuppressWarnings("unchecked")
     static <V,A> void invokeUnchecked(CompletionHandler<V,? super A> handler,
-                                      AbstractFuture<V,A> result)
+                                      A attachment,
+                                      V value,
+                                      Throwable exc)
     {
-        if (handler != null && !result.isCancelled()) {
-            Throwable exc = result.exception();
-            if (exc == null) {
-                handler.completed(result.value(), result.attachment());
-            } else {
-                handler.failed(exc, result.attachment());
-            }
+        if (exc == null) {
+            handler.completed(value, attachment);
+        } else {
+            handler.failed(exc, attachment);
+        }
 
-            // clear interrupt
-            Thread.interrupted();
-        }
+        // clear interrupt
+        Thread.interrupted();
     }
 
-
     /**
-     * Invoke handler after incrementing the invoke count.
+     * Invoke handler assuming thread identity already checked
      */
     static <V,A> void invokeDirect(GroupAndInvokeCount myGroupAndInvokeCount,
                                    CompletionHandler<V,? super A> handler,
-                                   AbstractFuture<V,A> result)
+                                   A attachment,
+                                   V result,
+                                   Throwable exc)
     {
         myGroupAndInvokeCount.incrementInvokeCount();
-        invokeUnchecked(handler, result);
+        Invoker.invokeUnchecked(handler, attachment, result, exc);
     }
 
     /**
@@ -151,64 +150,64 @@
      * thread pool then the handler is invoked directly, otherwise it is
      * invoked indirectly.
      */
-    static <V,A> void invoke(CompletionHandler<V,? super A> handler,
-                             AbstractFuture<V,A> result)
+    static <V,A> void invoke(AsynchronousChannel channel,
+                             CompletionHandler<V,? super A> handler,
+                             A attachment,
+                             V result,
+                             Throwable exc)
     {
-        if (handler != null) {
-            boolean invokeDirect = false;
-            boolean identityOkay = false;
-            GroupAndInvokeCount thisGroupAndInvokeCount = myGroupAndInvokeCount.get();
-            if (thisGroupAndInvokeCount != null) {
-                AsynchronousChannel channel = result.channel();
-                if ((thisGroupAndInvokeCount.group() == ((Groupable)channel).group()))
-                    identityOkay = true;
-                if (identityOkay &&
-                    (thisGroupAndInvokeCount.invokeCount() < maxHandlerInvokeCount))
-                {
-                    // group match
-                    invokeDirect = true;
-                }
+        boolean invokeDirect = false;
+        boolean identityOkay = false;
+        GroupAndInvokeCount thisGroupAndInvokeCount = myGroupAndInvokeCount.get();
+        if (thisGroupAndInvokeCount != null) {
+            if ((thisGroupAndInvokeCount.group() == ((Groupable)channel).group()))
+                identityOkay = true;
+            if (identityOkay &&
+                (thisGroupAndInvokeCount.invokeCount() < maxHandlerInvokeCount))
+            {
+                // group match
+                invokeDirect = true;
             }
-            if (invokeDirect) {
-                thisGroupAndInvokeCount.incrementInvokeCount();
-                invokeUnchecked(handler, result);
-            } else {
-                try {
-                    invokeIndirectly(handler, result);
-                } catch (RejectedExecutionException ree) {
-                    // channel group shutdown; fallback to invoking directly
-                    // if the current thread has the right identity.
-                    if (identityOkay) {
-                        invokeUnchecked(handler, result);
-                    } else {
-                        throw new ShutdownChannelGroupException();
-                    }
+        }
+        if (invokeDirect) {
+            invokeDirect(thisGroupAndInvokeCount, handler, attachment, result, exc);
+        } else {
+            try {
+                invokeIndirectly(channel, handler, attachment, result, exc);
+            } catch (RejectedExecutionException ree) {
+                // channel group shutdown; fallback to invoking directly
+                // if the current thread has the right identity.
+                if (identityOkay) {
+                    invokeDirect(thisGroupAndInvokeCount,
+                                 handler, attachment, result, exc);
+                } else {
+                    throw new ShutdownChannelGroupException();
                 }
             }
         }
     }
 
     /**
-     * Invokes the handler "indirectly" in the channel group's thread pool.
+     * Invokes the handler indirectly via the channel group's thread pool.
      */
-    static <V,A> void invokeIndirectly(final CompletionHandler<V,? super A> handler,
-                                       final AbstractFuture<V,A> result)
+    static <V,A> void invokeIndirectly(AsynchronousChannel channel,
+                                       final CompletionHandler<V,? super A> handler,
+                                       final A attachment,
+                                       final V result,
+                                       final Throwable exc)
     {
-        if (handler != null) {
-            AsynchronousChannel channel = result.channel();
-            try {
-                ((Groupable)channel).group().executeOnPooledThread(new Runnable() {
-                    public void run() {
-                        GroupAndInvokeCount thisGroupAndInvokeCount =
-                            myGroupAndInvokeCount.get();
-                        if (thisGroupAndInvokeCount != null)
-                            thisGroupAndInvokeCount.setInvokeCount(1);
-                        invokeUnchecked(handler, result);
-                    }
-                });
-            } catch (RejectedExecutionException ree) {
-                throw new ShutdownChannelGroupException();
-            }
+        try {
+            ((Groupable)channel).group().executeOnPooledThread(new Runnable() {
+                public void run() {
+                    GroupAndInvokeCount thisGroupAndInvokeCount =
+                        myGroupAndInvokeCount.get();
+                    if (thisGroupAndInvokeCount != null)
+                        thisGroupAndInvokeCount.setInvokeCount(1);
+                    invokeUnchecked(handler, attachment, result, exc);
+                }
+            });
+        } catch (RejectedExecutionException ree) {
+            throw new ShutdownChannelGroupException();
         }
     }
 
@@ -216,19 +215,19 @@
      * Invokes the handler "indirectly" in the given Executor
      */
     static <V,A> void invokeIndirectly(final CompletionHandler<V,? super A> handler,
-                                       final AbstractFuture<V,A> result,
+                                       final A attachment,
+                                       final V value,
+                                       final Throwable exc,
                                        Executor executor)
     {
-        if (handler != null) {
-            try {
-                executor.execute(new Runnable() {
-                    public void run() {
-                        invokeUnchecked(handler, result);
-                    }
-                });
-            } catch (RejectedExecutionException ree) {
-                throw new ShutdownChannelGroupException();
-            }
+         try {
+            executor.execute(new Runnable() {
+                public void run() {
+                    invokeUnchecked(handler, attachment, value, exc);
+                }
+            });
+        } catch (RejectedExecutionException ree) {
+            throw new ShutdownChannelGroupException();
         }
     }
 
@@ -258,4 +257,52 @@
             throw new ShutdownChannelGroupException();
         }
     }
+
+    /**
+     * Invoke handler with completed result. This method does not check the
+     * thread identity or the number of handlers on the thread stack.
+     */
+    static <V,A> void invokeUnchecked(PendingFuture<V,A> future) {
+        assert future.isDone();
+        CompletionHandler<V,? super A> handler = future.handler();
+        if (handler != null) {
+            invokeUnchecked(handler,
+                            future.attachment(),
+                            future.value(),
+                            future.exception());
+        }
+    }
+
+    /**
+     * Invoke handler with completed result. If the current thread is in the
+     * channel group's thread pool then the handler is invoked directly,
+     * otherwise it is invoked indirectly.
+     */
+    static <V,A> void invoke(PendingFuture<V,A> future) {
+        assert future.isDone();
+        CompletionHandler<V,? super A> handler = future.handler();
+        if (handler != null) {
+            invoke(future.channel(),
+                   handler,
+                   future.attachment(),
+                   future.value(),
+                   future.exception());
+        }
+    }
+
+    /**
+     * Invoke handler with completed result. The handler is invoked indirectly,
+     * via the channel group's thread pool.
+     */
+    static <V,A> void invokeIndirectly(PendingFuture<V,A> future) {
+        assert future.isDone();
+        CompletionHandler<V,? super A> handler = future.handler();
+        if (handler != null) {
+            invokeIndirectly(future.channel(),
+                             handler,
+                             future.attachment(),
+                             future.value(),
+                             future.exception());
+        }
+    }
 }
--- a/src/share/classes/sun/nio/ch/PendingFuture.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/sun/nio/ch/PendingFuture.java	Sun Aug 23 12:53:45 2009 +0100
@@ -34,13 +34,13 @@
  * attachment of an additional arbitrary context object and a timer task.
  */
 
-final class PendingFuture<V,A>
-    extends AbstractFuture<V,A>
-{
+final class PendingFuture<V,A> implements Future<V> {
     private static final CancellationException CANCELLED =
         new CancellationException();
 
+    private final AsynchronousChannel channel;
     private final CompletionHandler<V,? super A> handler;
+    private final A attachment;
 
     // true if result (or exception) is available
     private volatile boolean haveResult;
@@ -56,14 +56,14 @@
     // optional context object
     private volatile Object context;
 
-
     PendingFuture(AsynchronousChannel channel,
                   CompletionHandler<V,? super A> handler,
                   A attachment,
                   Object context)
     {
-        super(channel, attachment);
+        this.channel = channel;
         this.handler = handler;
+        this.attachment = attachment;
         this.context = context;
     }
 
@@ -71,14 +71,31 @@
                   CompletionHandler<V,? super A> handler,
                   A attachment)
     {
-        super(channel, attachment);
+        this.channel = channel;
         this.handler = handler;
+        this.attachment = attachment;
+    }
+
+    PendingFuture(AsynchronousChannel channel) {
+        this(channel, null, null);
+    }
+
+    PendingFuture(AsynchronousChannel channel, Object context) {
+        this(channel, null, null, context);
+    }
+
+    AsynchronousChannel channel() {
+        return channel;
     }
 
     CompletionHandler<V,? super A> handler() {
         return handler;
     }
 
+    A attachment() {
+        return attachment;
+    }
+
     void setContext(Object context) {
         this.context = context;
     }
@@ -113,36 +130,45 @@
     /**
      * Sets the result, or a no-op if the result or exception is already set.
      */
-    boolean setResult(V res) {
+    void setResult(V res) {
         synchronized (this) {
             if (haveResult)
-                return false;
+                return;
             result = res;
             haveResult = true;
             if (timeoutTask != null)
                 timeoutTask.cancel(false);
             if (latch != null)
                 latch.countDown();
-            return true;
         }
     }
 
     /**
      * Sets the result, or a no-op if the result or exception is already set.
      */
-    boolean setFailure(Throwable x) {
+    void setFailure(Throwable x) {
         if (!(x instanceof IOException) && !(x instanceof SecurityException))
             x = new IOException(x);
         synchronized (this) {
             if (haveResult)
-                return false;
+                return;
             exc = x;
             haveResult = true;
             if (timeoutTask != null)
                 timeoutTask.cancel(false);
             if (latch != null)
                 latch.countDown();
-            return true;
+        }
+    }
+
+    /**
+     * Sets the result
+     */
+    void setResult(V res, Throwable x) {
+        if (x == null) {
+            setResult(res);
+        } else {
+            setFailure(x);
         }
     }
 
@@ -178,12 +204,10 @@
         return result;
     }
 
-    @Override
     Throwable exception() {
         return (exc != CANCELLED) ? exc : null;
     }
 
-    @Override
     V value() {
         return result;
     }
@@ -204,33 +228,6 @@
             if (haveResult)
                 return false;    // already completed
 
-            // A shutdown of the channel group will close all channels and
-            // shutdown the executor. To ensure that the completion handler
-            // is executed we queue the task while holding the lock.
-            if (handler != null) {
-                prepareForWait();
-                Runnable cancelTask = new Runnable() {
-                    public void run() {
-                        while (!haveResult) {
-                            try {
-                                latch.await();
-                            } catch (InterruptedException ignore) { }
-                        }
-                        handler.cancelled(attachment());
-                    }
-                };
-                AsynchronousChannel ch = channel();
-                if (ch instanceof Groupable) {
-                    ((Groupable)ch).group().executeOnPooledThread(cancelTask);
-                } else {
-                    if (ch instanceof AsynchronousFileChannelImpl) {
-                        ((AsynchronousFileChannelImpl)ch).executor().execute(cancelTask);
-                    } else {
-                        throw new AssertionError("Should not get here");
-                    }
-                }
-            }
-
             // notify channel
             if (channel() instanceof Cancellable)
                 ((Cancellable)channel()).onCancel(this);
@@ -249,7 +246,7 @@
             } catch (IOException ignore) { }
         }
 
-        // release waiters (this also releases the invoker)
+        // release waiters
         if (latch != null)
             latch.countDown();
         return true;
--- a/src/share/classes/sun/nio/ch/SimpleAsynchronousDatagramChannelImpl.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/sun/nio/ch/SimpleAsynchronousDatagramChannelImpl.java	Sun Aug 23 12:53:45 2009 +0100
@@ -317,51 +317,71 @@
         return new WrappedMembershipKey(this, key);
     }
 
-    @Override
-    public <A> Future<Integer> send(ByteBuffer src,
-                                    SocketAddress target,
-                                    long timeout,
-                                    TimeUnit unit,
-                                    A attachment,
-                                    CompletionHandler<Integer,? super A> handler)
+    private <A> Future<Integer> implSend(ByteBuffer src,
+                                         SocketAddress target,
+                                         A attachment,
+                                         CompletionHandler<Integer,? super A> handler)
     {
-        if (timeout < 0L)
-            throw new IllegalArgumentException("Negative timeout");
-        if (unit == null)
-            throw new NullPointerException();
-
-        CompletedFuture<Integer,A> result;
+        int n = 0;
+        Throwable exc = null;
         try {
-            int n = dc.send(src, target);
-            result = CompletedFuture.withResult(this, n, attachment);
+            n = dc.send(src, target);
         } catch (IOException ioe) {
-            result = CompletedFuture.withFailure(this, ioe, attachment);
+            exc = ioe;
         }
-        Invoker.invoke(handler, result);
-        return result;
+        if (handler == null)
+            return CompletedFuture.withResult(n, exc);
+        Invoker.invoke(this, handler, attachment, n, exc);
+        return null;
     }
 
     @Override
-    public <A> Future<Integer> write(ByteBuffer src,
-                                     long timeout,
-                                     TimeUnit unit,
-                                     A attachment,
-                                     CompletionHandler<Integer,? super A> handler)
+    public Future<Integer> send(ByteBuffer src, SocketAddress target) {
+        return implSend(src, target, null, null);
+    }
+
+    @Override
+    public <A> void send(ByteBuffer src,
+                         SocketAddress target,
+                         A attachment,
+                         CompletionHandler<Integer,? super A> handler)
     {
-        if (timeout < 0L)
-            throw new IllegalArgumentException("Negative timeout");
-        if (unit == null)
-            throw new NullPointerException();
+        if (handler == null)
+            throw new NullPointerException("'handler' is null");
+        implSend(src, target, attachment, handler);
+    }
 
-        CompletedFuture<Integer,A> result;
+    private <A> Future<Integer> implWrite(ByteBuffer src,
+                                          A attachment,
+                                          CompletionHandler<Integer,? super A> handler)
+    {
+        int n = 0;
+        Throwable exc = null;
         try {
-            int n = dc.write(src);
-            result = CompletedFuture.withResult(this, n, attachment);
+            n = dc.write(src);
         } catch (IOException ioe) {
-            result = CompletedFuture.withFailure(this, ioe, attachment);
+            exc = ioe;
         }
-        Invoker.invoke(handler, result);
-        return result;
+        if (handler == null)
+            return CompletedFuture.withResult(n, exc);
+        Invoker.invoke(this, handler, attachment, n, exc);
+        return null;
+
+    }
+
+    @Override
+    public Future<Integer> write(ByteBuffer src) {
+        return implWrite(src, null, null);
+    }
+
+    @Override
+    public <A> void write(ByteBuffer src,
+                          A attachment,
+                          CompletionHandler<Integer,? super A> handler)
+    {
+        if (handler == null)
+            throw new NullPointerException("'handler' is null");
+        implWrite(src, attachment, handler);
     }
 
     /**
@@ -390,12 +410,11 @@
         }
     }
 
-    @Override
-    public <A> Future<SocketAddress> receive(final ByteBuffer dst,
-                                             final long timeout,
-                                             final TimeUnit unit,
-                                             A attachment,
-                                             final CompletionHandler<SocketAddress,? super A> handler)
+    private <A> Future<SocketAddress> implReceive(final ByteBuffer dst,
+                                                  final long timeout,
+                                                  final TimeUnit unit,
+                                                  A attachment,
+                                                  final CompletionHandler<SocketAddress,? super A> handler)
     {
         if (dst.isReadOnly())
             throw new IllegalArgumentException("Read-only buffer");
@@ -406,10 +425,11 @@
 
         // complete immediately if channel closed
         if (!isOpen()) {
-            CompletedFuture<SocketAddress,A> result = CompletedFuture.withFailure(this,
-                new ClosedChannelException(), attachment);
-            Invoker.invoke(handler, result);
-            return result;
+            Throwable exc = new ClosedChannelException();
+            if (handler == null)
+                return CompletedFuture.withFailure(exc);
+            Invoker.invoke(this, handler, attachment, null, exc);
+            return null;
         }
 
         final AccessControlContext acc = (System.getSecurityManager() == null) ?
@@ -471,7 +491,7 @@
                         x = new AsynchronousCloseException();
                     result.setFailure(x);
                 }
-                Invoker.invokeUnchecked(handler, result);
+                Invoker.invokeUnchecked(result);
             }
         };
         try {
@@ -483,11 +503,27 @@
     }
 
     @Override
-    public <A> Future<Integer> read(final ByteBuffer dst,
-                                    final long timeout,
-                                    final TimeUnit unit,
-                                    A attachment,
-                                    final CompletionHandler<Integer,? super A> handler)
+    public Future<SocketAddress> receive(ByteBuffer dst) {
+        return implReceive(dst, 0L, TimeUnit.MILLISECONDS, null, null);
+    }
+
+    @Override
+    public <A> void receive(ByteBuffer dst,
+                            long timeout,
+                            TimeUnit unit,
+                            A attachment,
+                            CompletionHandler<SocketAddress,? super A> handler)
+    {
+        if (handler == null)
+            throw new NullPointerException("'handler' is null");
+        implReceive(dst, timeout, unit, attachment, handler);
+    }
+
+    private <A> Future<Integer> implRead(final ByteBuffer dst,
+                                         final long timeout,
+                                         final TimeUnit unit,
+                                         A attachment,
+                                         final CompletionHandler<Integer,? super A> handler)
     {
         if (dst.isReadOnly())
             throw new IllegalArgumentException("Read-only buffer");
@@ -495,18 +531,20 @@
             throw new IllegalArgumentException("Negative timeout");
         if (unit == null)
             throw new NullPointerException();
+
+        // complete immediately if channel closed
+        if (!isOpen()) {
+            Throwable exc = new ClosedChannelException();
+            if (handler == null)
+                return CompletedFuture.withFailure(exc);
+            Invoker.invoke(this, handler, attachment, null, exc);
+            return null;
+        }
+
         // another thread may disconnect before read is initiated
         if (!dc.isConnected())
             throw new NotYetConnectedException();
 
-        // complete immediately if channel closed
-        if (!isOpen()) {
-            CompletedFuture<Integer,A> result = CompletedFuture.withFailure(this,
-                new ClosedChannelException(), attachment);
-            Invoker.invoke(handler, result);
-            return result;
-        }
-
         final PendingFuture<Integer,A> result =
             new PendingFuture<Integer,A>(this, handler, attachment);
         Runnable task = new Runnable() {
@@ -563,7 +601,7 @@
                         x = new AsynchronousCloseException();
                     result.setFailure(x);
                 }
-                Invoker.invokeUnchecked(handler, result);
+                Invoker.invokeUnchecked(result);
             }
         };
         try {
@@ -575,6 +613,23 @@
     }
 
     @Override
+    public Future<Integer> read(ByteBuffer dst) {
+        return implRead(dst, 0L, TimeUnit.MILLISECONDS, null, null);
+    }
+
+    @Override
+    public <A> void read(ByteBuffer dst,
+                            long timeout,
+                            TimeUnit unit,
+                            A attachment,
+                            CompletionHandler<Integer,? super A> handler)
+    {
+        if (handler == null)
+            throw new NullPointerException("'handler' is null");
+        implRead(dst, timeout, unit, attachment, handler);
+    }
+
+    @Override
     public  AsynchronousDatagramChannel bind(SocketAddress local)
         throws IOException
     {
--- a/src/share/classes/sun/nio/ch/SimpleAsynchronousFileChannelImpl.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/share/classes/sun/nio/ch/SimpleAsynchronousFileChannelImpl.java	Sun Aug 23 12:53:45 2009 +0100
@@ -50,9 +50,6 @@
     // Used to make native read and write calls
     private static final FileDispatcher nd = new FileDispatcherImpl();
 
-    // indicates if the associated thread pool is the default thread pool
-    private final boolean isDefaultExecutor;
-
     // Thread-safe set of IDs of native threads, for signalling
     private final NativeThreadSet threads = new NativeThreadSet(2);
 
@@ -60,11 +57,9 @@
     SimpleAsynchronousFileChannelImpl(FileDescriptor fdObj,
                                       boolean reading,
                                       boolean writing,
-                                      ExecutorService executor,
-                                      boolean isDefaultexecutor)
+                                      ExecutorService executor)
     {
         super(fdObj, reading, writing, executor);
-        this.isDefaultExecutor = isDefaultexecutor;
     }
 
     public static AsynchronousFileChannel open(FileDescriptor fdo,
@@ -73,17 +68,9 @@
                                                ThreadPool pool)
     {
         // Executor is either default or based on pool parameters
-        ExecutorService executor;
-        boolean isDefaultexecutor;
-        if (pool == null) {
-            executor = DefaultExecutorHolder.defaultExecutor;
-            isDefaultexecutor = true;
-        } else {
-            executor = pool.executor();
-            isDefaultexecutor = false;
-        }
-        return new SimpleAsynchronousFileChannelImpl(fdo,
-            reading, writing, executor, isDefaultexecutor);
+        ExecutorService executor = (pool == null) ?
+            DefaultExecutorHolder.defaultExecutor : pool.executor();
+        return new SimpleAsynchronousFileChannelImpl(fdo, reading, writing, executor);
     }
 
     @Override
@@ -114,16 +101,6 @@
 
         // close file
         nd.close(fdObj);
-
-        // shutdown executor if specific to this channel
-        if (!isDefaultExecutor) {
-            AccessController.doPrivileged(new PrivilegedAction<Void>() {
-                public Void run() {
-                    executor.shutdown();
-                    return null;
-                }
-            });
-        }
     }
 
     @Override
@@ -194,11 +171,11 @@
     }
 
     @Override
-    public <A> Future<FileLock> lock(final long position,
-                                     final long size,
-                                     final boolean shared,
-                                     A attachment,
-                                     final CompletionHandler<FileLock,? super A> handler)
+    <A> Future<FileLock> implLock(final long position,
+                                  final long size,
+                                  final boolean shared,
+                                  final A attachment,
+                                  final CompletionHandler<FileLock,? super A> handler)
     {
         if (shared && !reading)
             throw new NonReadableChannelException();
@@ -208,16 +185,19 @@
         // add to lock table
         final FileLockImpl fli = addToFileLockTable(position, size, shared);
         if (fli == null) {
-            CompletedFuture<FileLock,A> result = CompletedFuture
-                .withFailure(this, new ClosedChannelException(), attachment);
-            Invoker.invokeIndirectly(handler, result, executor);
-            return result;
+            Throwable exc = new ClosedChannelException();
+            if (handler == null)
+                return CompletedFuture.withFailure(exc);
+            Invoker.invokeIndirectly(handler, attachment, null, exc, executor);
+            return null;
         }
 
-        final PendingFuture<FileLock,A> result =
-            new PendingFuture<FileLock,A>(this, handler, attachment);
+        final PendingFuture<FileLock,A> result = (handler == null) ?
+            new PendingFuture<FileLock,A>(this) : null;
         Runnable task = new Runnable() {
             public void run() {
+                Throwable exc = null;
+
                 int ti = threads.add();
                 try {
                     int n;
@@ -226,31 +206,36 @@
                         do {
                             n = nd.lock(fdObj, true, position, size, shared);
                         } while ((n == FileDispatcher.INTERRUPTED) && isOpen());
-                        if (n == FileDispatcher.LOCKED && isOpen()) {
-                            result.setResult(fli);
-                        } else {
+                        if (n != FileDispatcher.LOCKED || !isOpen()) {
                             throw new AsynchronousCloseException();
                         }
                     } catch (IOException x) {
                         removeFromFileLockTable(fli);
                         if (!isOpen())
                             x = new AsynchronousCloseException();
-                        result.setFailure(x);
+                        exc = x;
                     } finally {
                         end();
                     }
                 } finally {
                     threads.remove(ti);
                 }
-                Invoker.invokeUnchecked(handler, result);
+                if (handler == null) {
+                    result.setResult(fli, exc);
+                } else {
+                    Invoker.invokeUnchecked(handler, attachment, fli, exc);
+                }
             }
         };
+        boolean executed = false;
         try {
             executor.execute(task);
-        } catch (RejectedExecutionException ree) {
-            // rollback
-            removeFromFileLockTable(fli);
-            throw new ShutdownChannelGroupException();
+            executed = true;
+        } finally {
+            if (!executed) {
+                // rollback
+                removeFromFileLockTable(fli);
+            }
         }
         return result;
     }
@@ -301,10 +286,10 @@
     }
 
     @Override
-    public <A> Future<Integer> read(final ByteBuffer dst,
-                                    final long position,
-                                    A attachment,
-                                    final CompletionHandler<Integer,? super A> handler)
+    <A> Future<Integer> implRead(final ByteBuffer dst,
+                                 final long position,
+                                 final A attachment,
+                                 final CompletionHandler<Integer,? super A> handler)
     {
         if (position < 0)
             throw new IllegalArgumentException("Negative position");
@@ -315,55 +300,52 @@
 
         // complete immediately if channel closed or no space remaining
         if (!isOpen() || (dst.remaining() == 0)) {
-            CompletedFuture<Integer,A> result;
-            if (isOpen()) {
-                result = CompletedFuture.withResult(this, 0, attachment);
-            } else {
-                result = CompletedFuture.withFailure(this,
-                    new ClosedChannelException(), attachment);
-            }
-            Invoker.invokeIndirectly(handler, result, executor);
-            return result;
+            Throwable exc = (isOpen()) ? null : new ClosedChannelException();
+            if (handler == null)
+                return CompletedFuture.withResult(0, exc);
+            Invoker.invokeIndirectly(handler, attachment, 0, exc, executor);
+            return null;
         }
 
-        final PendingFuture<Integer,A> result =
-            new PendingFuture<Integer,A>(this, handler, attachment);
+        final PendingFuture<Integer,A> result = (handler == null) ?
+            new PendingFuture<Integer,A>(this) : null;
         Runnable task = new Runnable() {
             public void run() {
+                int n = 0;
+                Throwable exc = null;
+
                 int ti = threads.add();
                 try {
                     begin();
-                    int n;
                     do {
                         n = IOUtil.read(fdObj, dst, position, nd, null);
                     } while ((n == IOStatus.INTERRUPTED) && isOpen());
                     if (n < 0 && !isOpen())
                         throw new AsynchronousCloseException();
-                    result.setResult(n);
                 } catch (IOException x) {
                     if (!isOpen())
                         x = new AsynchronousCloseException();
-                    result.setFailure(x);
+                    exc = x;
                 } finally {
                     end();
                     threads.remove(ti);
                 }
-                Invoker.invokeUnchecked(handler, result);
+                if (handler == null) {
+                    result.setResult(n, exc);
+                } else {
+                    Invoker.invokeUnchecked(handler, attachment, n, exc);
+                }
             }
         };
-        try {
-            executor.execute(task);
-        } catch (RejectedExecutionException ree) {
-            throw new ShutdownChannelGroupException();
-        }
+        executor.execute(task);
         return result;
     }
 
     @Override
-    public <A> Future<Integer> write(final ByteBuffer src,
-                                     final long position,
-                                     A attachment,
-                                     final CompletionHandler<Integer,? super A> handler)
+    <A> Future<Integer> implWrite(final ByteBuffer src,
+                                  final long position,
+                                  final A attachment,
+                                  final CompletionHandler<Integer,? super A> handler)
     {
         if (position < 0)
             throw new IllegalArgumentException("Negative position");
@@ -372,47 +354,44 @@
 
         // complete immediately if channel is closed or no bytes remaining
         if (!isOpen() || (src.remaining() == 0)) {
-            CompletedFuture<Integer,A> result;
-            if (isOpen()) {
-                result = CompletedFuture.withResult(this, 0, attachment);
-            } else {
-                result = CompletedFuture.withFailure(this,
-                    new ClosedChannelException(), attachment);
-            }
-            Invoker.invokeIndirectly(handler, result, executor);
-            return result;
+            Throwable exc = (isOpen()) ? null : new ClosedChannelException();
+            if (handler == null)
+                return CompletedFuture.withResult(0, exc);
+            Invoker.invokeIndirectly(handler, attachment, 0, exc, executor);
+            return null;
         }
 
-        final PendingFuture<Integer,A> result =
-            new PendingFuture<Integer,A>(this, handler, attachment);
+        final PendingFuture<Integer,A> result = (handler == null) ?
+            new PendingFuture<Integer,A>(this) : null;
         Runnable task = new Runnable() {
             public void run() {
+                int n = 0;
+                Throwable exc = null;
+
                 int ti = threads.add();
                 try {
                     begin();
-                    int n;
                     do {
                         n = IOUtil.write(fdObj, src, position, nd, null);
                     } while ((n == IOStatus.INTERRUPTED) && isOpen());
                     if (n < 0 && !isOpen())
                         throw new AsynchronousCloseException();
-                    result.setResult(n);
                 } catch (IOException x) {
                     if (!isOpen())
                         x = new AsynchronousCloseException();
-                    result.setFailure(x);
+                    exc = x;
                 } finally {
                     end();
                     threads.remove(ti);
                 }
-                Invoker.invokeUnchecked(handler, result);
+                if (handler == null) {
+                    result.setResult(n, exc);
+                } else {
+                    Invoker.invokeUnchecked(handler, attachment, n, exc);
+                }
             }
         };
-        try {
-            executor.execute(task);
-        } catch (RejectedExecutionException ree) {
-            throw new ShutdownChannelGroupException();
-        }
+        executor.execute(task);
         return result;
     }
 }
--- a/src/solaris/classes/sun/nio/ch/EPollPort.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/solaris/classes/sun/nio/ch/EPollPort.java	Sun Aug 23 12:53:45 2009 +0100
@@ -248,12 +248,13 @@
         public void run() {
             Invoker.GroupAndInvokeCount myGroupAndInvokeCount =
                 Invoker.getGroupAndInvokeCount();
+            final boolean isPooledThread = (myGroupAndInvokeCount != null);
             boolean replaceMe = false;
             Event ev;
             try {
                 for (;;) {
                     // reset invoke count
-                    if (myGroupAndInvokeCount != null)
+                    if (isPooledThread)
                         myGroupAndInvokeCount.resetInvokeCount();
 
                     try {
@@ -289,7 +290,7 @@
 
                     // process event
                     try {
-                        ev.channel().onEvent(ev.events());
+                        ev.channel().onEvent(ev.events(), isPooledThread);
                     } catch (Error x) {
                         replaceMe = true; throw x;
                     } catch (RuntimeException x) {
--- a/src/solaris/classes/sun/nio/ch/Port.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/solaris/classes/sun/nio/ch/Port.java	Sun Aug 23 12:53:45 2009 +0100
@@ -49,7 +49,7 @@
      * Implemented by clients registered with this port.
      */
     interface PollableChannel extends Closeable {
-        void onEvent(int events);
+        void onEvent(int events, boolean mayInvokeDirect);
     }
 
     // maps fd to "pollable" channel
@@ -121,7 +121,7 @@
     final Object attachForeignChannel(final Channel channel, FileDescriptor fd) {
         int fdVal = IOUtil.fdVal(fd);
         register(fdVal, new PollableChannel() {
-            public void onEvent(int events) { }
+            public void onEvent(int events, boolean mayInvokeDirect) { }
             public void close() throws IOException {
                 channel.close();
             }
--- a/src/solaris/classes/sun/nio/ch/SolarisEventPort.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/solaris/classes/sun/nio/ch/SolarisEventPort.java	Sun Aug 23 12:53:45 2009 +0100
@@ -151,12 +151,13 @@
         public void run() {
             Invoker.GroupAndInvokeCount myGroupAndInvokeCount =
                 Invoker.getGroupAndInvokeCount();
+            final boolean isPooledThread = (myGroupAndInvokeCount != null);
             boolean replaceMe = false;
             long address = unsafe.allocateMemory(SIZEOF_PORT_EVENT);
             try {
                 for (;;) {
                     // reset invoke count
-                    if (myGroupAndInvokeCount != null)
+                    if (isPooledThread)
                         myGroupAndInvokeCount.resetInvokeCount();
 
                     // wait for I/O completion event
@@ -205,7 +206,7 @@
                     if (ch != null) {
                         replaceMe = true;
                         // no need to translate events
-                        ch.onEvent(events);
+                        ch.onEvent(events, isPooledThread);
                     }
                 }
             } finally {
--- a/src/solaris/classes/sun/nio/ch/UnixAsynchronousServerSocketChannelImpl.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/solaris/classes/sun/nio/ch/UnixAsynchronousServerSocketChannelImpl.java	Sun Aug 23 12:53:45 2009 +0100
@@ -59,10 +59,13 @@
     private final Object updateLock = new Object();
 
     // pending accept
-    private PendingFuture<AsynchronousSocketChannel,Object> pendingAccept;
+    private boolean acceptPending;
+    private CompletionHandler<AsynchronousSocketChannel,Object> acceptHandler;
+    private Object acceptAttachment;
+    private PendingFuture<AsynchronousSocketChannel,Object> acceptFuture;
 
     // context for permission check when security manager set
-    private AccessControlContext acc;
+    private AccessControlContext acceptAcc;
 
 
     UnixAsynchronousServerSocketChannelImpl(Port port)
@@ -83,15 +86,6 @@
         port.register(fdVal, this);
     }
 
-    // returns and clears the result of a pending accept
-    private PendingFuture<AsynchronousSocketChannel,Object> grabPendingAccept() {
-        synchronized (updateLock) {
-            PendingFuture<AsynchronousSocketChannel,Object> result = pendingAccept;
-            pendingAccept = null;
-            return result;
-        }
-    }
-
     @Override
     void implClose() throws IOException {
         // remove the mapping
@@ -101,17 +95,27 @@
         nd.close(fd);
 
         // if there is a pending accept then complete it
-        final PendingFuture<AsynchronousSocketChannel,Object> result =
-            grabPendingAccept();
-        if (result != null) {
-            // discard the stack trace as otherwise it may appear that implClose
-            // has thrown the exception.
-            AsynchronousCloseException x = new AsynchronousCloseException();
-            x.setStackTrace(new StackTraceElement[0]);
-            result.setFailure(x);
+        CompletionHandler<AsynchronousSocketChannel,Object> handler;
+        Object att;
+        PendingFuture<AsynchronousSocketChannel,Object> future;
+        synchronized (updateLock) {
+            if (!acceptPending)
+                return;  // no pending accept
+            acceptPending = false;
+            handler = acceptHandler;
+            att = acceptAttachment;
+            future = acceptFuture;
+        }
 
+        // discard the stack trace as otherwise it may appear that implClose
+        // has thrown the exception.
+        AsynchronousCloseException x = new AsynchronousCloseException();
+        x.setStackTrace(new StackTraceElement[0]);
+        if (handler == null) {
+            future.setFailure(x);
+        } else {
             // invoke by submitting task rather than directly
-            Invoker.invokeIndirectly(result.handler(), result);
+            Invoker.invokeIndirectly(this, handler, att, null, x);
         }
     }
 
@@ -124,15 +128,17 @@
      * Invoked by event handling thread when listener socket is polled
      */
     @Override
-    public void onEvent(int events) {
-        PendingFuture<AsynchronousSocketChannel,Object> result = grabPendingAccept();
-        if (result == null)
-            return; // may have been grabbed by asynchronous close
+    public void onEvent(int events, boolean mayInvokeDirect) {
+        synchronized (updateLock) {
+            if (!acceptPending)
+                return;  // may have been grabbed by asynchronous close
+            acceptPending = false;
+        }
 
         // attempt to accept connection
         FileDescriptor newfd = new FileDescriptor();
         InetSocketAddress[] isaa = new InetSocketAddress[1];
-        boolean accepted = false;
+        Throwable exc = null;
         try {
             begin();
             int n = accept0(this.fd, newfd, isaa);
@@ -140,49 +146,52 @@
             // spurious wakeup, is this possible?
             if (n == IOStatus.UNAVAILABLE) {
                 synchronized (updateLock) {
-                    this.pendingAccept = result;
+                    acceptPending = true;
                 }
                 port.startPoll(fdVal, Port.POLLIN);
                 return;
             }
 
-            // connection accepted
-            accepted = true;
-
         } catch (Throwable x) {
             if (x instanceof ClosedChannelException)
                 x = new AsynchronousCloseException();
-            enableAccept();
-            result.setFailure(x);
+            exc = x;
         } finally {
             end();
         }
 
         // Connection accepted so finish it when not holding locks.
         AsynchronousSocketChannel child = null;
-        if (accepted) {
+        if (exc == null) {
             try {
-                child = finishAccept(newfd, isaa[0], acc);
-                enableAccept();
-                result.setResult(child);
+                child = finishAccept(newfd, isaa[0], acceptAcc);
             } catch (Throwable x) {
-                enableAccept();
                 if (!(x instanceof IOException) && !(x instanceof SecurityException))
                     x = new IOException(x);
-                result.setFailure(x);
+                exc = x;
             }
         }
 
-        // if an async cancel has already cancelled the operation then
-        // close the new channel so as to free resources
-        if (child != null && result.isCancelled()) {
-            try {
-                child.close();
-            } catch (IOException ignore) { }
+        // copy field befores accept is re-renabled
+        CompletionHandler<AsynchronousSocketChannel,Object> handler = acceptHandler;
+        Object att = acceptAttachment;
+        PendingFuture<AsynchronousSocketChannel,Object> future = acceptFuture;
+
+        // re-enable accepting and invoke handler
+        enableAccept();
+
+        if (handler == null) {
+            future.setResult(child, exc);
+            // if an async cancel has already cancelled the operation then
+            // close the new channel so as to free resources
+            if (child != null && future.isCancelled()) {
+                try {
+                    child.close();
+                } catch (IOException ignore) { }
+            }
+        } else {
+            Invoker.invoke(this, handler, att, child, exc);
         }
-
-        // invoke the handler
-        Invoker.invoke(result.handler(), result);
     }
 
     /**
@@ -234,16 +243,18 @@
     }
 
     @Override
-    @SuppressWarnings("unchecked")
-    public <A> Future<AsynchronousSocketChannel> accept(A attachment,
-        final CompletionHandler<AsynchronousSocketChannel,? super A> handler)
+    Future<AsynchronousSocketChannel> implAccept(Object att,
+        CompletionHandler<AsynchronousSocketChannel,Object> handler)
     {
         // complete immediately if channel is closed
         if (!isOpen()) {
-            CompletedFuture<AsynchronousSocketChannel,A> result = CompletedFuture
-                .withFailure(this, new ClosedChannelException(), attachment);
-            Invoker.invokeIndirectly(handler, result);
-            return result;
+            Throwable e = new ClosedChannelException();
+            if (handler == null) {
+                return CompletedFuture.withFailure(e);
+            } else {
+                Invoker.invoke(this, handler, att, null, e);
+                return null;
+            }
         }
         if (localAddress == null)
             throw new NotYetBoundException();
@@ -258,25 +269,31 @@
             throw new AcceptPendingException();
 
         // attempt accept
-        AbstractFuture<AsynchronousSocketChannel,A> result = null;
         FileDescriptor newfd = new FileDescriptor();
         InetSocketAddress[] isaa = new InetSocketAddress[1];
+        Throwable exc = null;
         try {
             begin();
 
             int n = accept0(this.fd, newfd, isaa);
             if (n == IOStatus.UNAVAILABLE) {
-                // no connection to accept
-                result = new PendingFuture<AsynchronousSocketChannel,A>(this, handler, attachment);
 
                 // need calling context when there is security manager as
                 // permission check may be done in a different thread without
                 // any application call frames on the stack
-                synchronized (this) {
-                    this.acc = (System.getSecurityManager() == null) ?
+                PendingFuture<AsynchronousSocketChannel,Object> result = null;
+                synchronized (updateLock) {
+                    if (handler == null) {
+                        this.acceptHandler = null;
+                        result = new PendingFuture<AsynchronousSocketChannel,Object>(this);
+                        this.acceptFuture = result;
+                    } else {
+                        this.acceptHandler = handler;
+                        this.acceptAttachment = att;
+                    }
+                    this.acceptAcc = (System.getSecurityManager() == null) ?
                         null : AccessController.getContext();
-                    this.pendingAccept =
-                        (PendingFuture<AsynchronousSocketChannel,Object>)result;
+                    this.acceptPending = true;
                 }
 
                 // register for connections
@@ -287,25 +304,30 @@
             // accept failed
             if (x instanceof ClosedChannelException)
                 x = new AsynchronousCloseException();
-            result = CompletedFuture.withFailure(this, x, attachment);
+            exc = x;
         } finally {
             end();
         }
 
-        // connection accepted immediately
-        if (result == null) {
+        AsynchronousSocketChannel child = null;
+        if (exc == null) {
+            // connection accepted immediately
             try {
-                AsynchronousSocketChannel ch = finishAccept(newfd, isaa[0], null);
-                result = CompletedFuture.withResult(this, ch, attachment);
+                child = finishAccept(newfd, isaa[0], null);
             } catch (Throwable x) {
-                result = CompletedFuture.withFailure(this, x, attachment);
+                exc = x;
             }
         }
 
-        // re-enable accepting and invoke handler
+        // re-enable accepting before invoking handler
         enableAccept();
-        Invoker.invokeIndirectly(handler, result);
-        return result;
+
+        if (handler == null) {
+            return CompletedFuture.withResult(child, exc);
+        } else {
+            Invoker.invokeIndirectly(this, handler, att, child, exc);
+            return null;
+        }
     }
 
     // -- Native methods --
--- a/src/solaris/classes/sun/nio/ch/UnixAsynchronousSocketChannelImpl.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/solaris/classes/sun/nio/ch/UnixAsynchronousSocketChannelImpl.java	Sun Aug 23 12:53:45 2009 +0100
@@ -61,20 +61,33 @@
     private final Object updateLock = new Object();
 
     // pending connect (updateLock)
-    private PendingFuture<Void,Object> pendingConnect;
+    private boolean connectPending;
+    private CompletionHandler<Void,Object> connectHandler;
+    private Object connectAttachment;
+    private PendingFuture<Void,Object> connectFuture;
 
-    // pending remote address (statLock)
+    // pending remote address (stateLock)
     private SocketAddress pendingRemote;
 
     // pending read (updateLock)
+    private boolean readPending;
+    private boolean isScatteringRead;
+    private ByteBuffer readBuffer;
     private ByteBuffer[] readBuffers;
-    private boolean scatteringRead;
-    private PendingFuture<Number,Object> pendingRead;
+    private CompletionHandler<Number,Object> readHandler;
+    private Object readAttachment;
+    private PendingFuture<Number,Object> readFuture;
+    private Future<?> readTimer;
 
     // pending write (updateLock)
+    private boolean writePending;
+    private boolean isGatheringWrite;
+    private ByteBuffer writeBuffer;
     private ByteBuffer[] writeBuffers;
-    private boolean gatheringWrite;
-    private PendingFuture<Number,Object> pendingWrite;
+    private CompletionHandler<Number,Object> writeHandler;
+    private Object writeAttachment;
+    private PendingFuture<Number,Object> writeFuture;
+    private Future<?> writeTimer;
 
 
     UnixAsynchronousSocketChannelImpl(Port port)
@@ -128,43 +141,36 @@
     private void updateEvents() {
         assert Thread.holdsLock(updateLock);
         int events = 0;
-        if (pendingRead != null)
+        if (readPending)
             events |= Port.POLLIN;
-        if (pendingConnect != null || pendingWrite != null)
+        if (connectPending || writePending)
             events |= Port.POLLOUT;
         if (events != 0)
             port.startPoll(fdVal, events);
     }
 
-    /**
-     * Invoked by event handler thread when file descriptor is polled
-     */
-    @Override
-    public void onEvent(int events) {
-        boolean readable = (events & Port.POLLIN) > 0;
-        boolean writable = (events & Port.POLLOUT) > 0;
-        if ((events & (Port.POLLERR | Port.POLLHUP)) > 0) {
-            readable = true;
-            writable = true;
-        }
-
-        PendingFuture<Void,Object> connectResult = null;
-        PendingFuture<Number,Object> readResult = null;
-        PendingFuture<Number,Object> writeResult = null;
+    // invoke to finish read and/or write operations
+    private void finish(boolean mayInvokeDirect,
+                        boolean readable,
+                        boolean writable)
+    {
+        boolean finishRead = false;
+        boolean finishWrite = false;
+        boolean finishConnect = false;
 
         // map event to pending result
         synchronized (updateLock) {
-            if (readable && (pendingRead != null)) {
-                readResult = pendingRead;
-                pendingRead = null;
+            if (readable && this.readPending) {
+                this.readPending = false;
+                finishRead = true;
             }
             if (writable) {
-                if (pendingWrite != null) {
-                    writeResult = pendingWrite;
-                    pendingWrite = null;
-                } else if (pendingConnect != null) {
-                    connectResult = pendingConnect;
-                    pendingConnect = null;
+                if (this.writePending) {
+                    this.writePending = false;
+                    finishWrite = true;
+                } else if (this.connectPending) {
+                    this.connectPending = false;
+                    finishConnect = true;
                 }
             }
         }
@@ -172,36 +178,32 @@
         // complete the I/O operation. Special case for when channel is
         // ready for both reading and writing. In that case, submit task to
         // complete write if write operation has a completion handler.
-        if (readResult != null) {
-            if (writeResult != null)
-                finishWrite(writeResult, false);
-            finishRead(readResult, true);
+        if (finishRead) {
+            if (finishWrite)
+                finishWrite(false);
+            finishRead(mayInvokeDirect);
             return;
         }
-        if (writeResult != null) {
-            finishWrite(writeResult, true);
+        if (finishWrite) {
+            finishWrite(mayInvokeDirect);
         }
-        if (connectResult != null) {
-            finishConnect(connectResult, true);
+        if (finishConnect) {
+            finishConnect(mayInvokeDirect);
         }
     }
 
-    // returns and clears the result of a pending read
-    PendingFuture<Number,Object> grabPendingRead() {
-        synchronized (updateLock) {
-            PendingFuture<Number,Object> result = pendingRead;
-            pendingRead = null;
-            return result;
+    /**
+     * Invoked by event handler thread when file descriptor is polled
+     */
+    @Override
+    public void onEvent(int events, boolean mayInvokeDirect) {
+        boolean readable = (events & Port.POLLIN) > 0;
+        boolean writable = (events & Port.POLLOUT) > 0;
+        if ((events & (Port.POLLERR | Port.POLLHUP)) > 0) {
+            readable = true;
+            writable = true;
         }
-    }
-
-    // returns and clears the result of a pending write
-    PendingFuture<Number,Object> grabPendingWrite() {
-        synchronized (updateLock) {
-            PendingFuture<Number,Object> result = pendingWrite;
-            pendingWrite = null;
-            return result;
-        }
+        finish(mayInvokeDirect, readable, writable);
     }
 
     @Override
@@ -213,26 +215,7 @@
         nd.close(fd);
 
         // All outstanding I/O operations are required to fail
-        final PendingFuture<Void,Object> readyToConnect;
-        final PendingFuture<Number,Object> readyToRead;
-        final PendingFuture<Number,Object> readyToWrite;
-        synchronized (updateLock) {
-            readyToConnect = pendingConnect;
-            pendingConnect = null;
-            readyToRead = pendingRead;
-            pendingRead = null;
-            readyToWrite = pendingWrite;
-            pendingWrite = null;
-        }
-        if (readyToConnect != null) {
-            finishConnect(readyToConnect, false);
-        }
-        if (readyToRead != null) {
-            finishRead(readyToRead, false);
-        }
-        if (readyToWrite != null) {
-            finishWrite(readyToWrite, false);
-        }
+        finish(false, true, true);
     }
 
     @Override
@@ -240,9 +223,9 @@
         if (task.getContext() == OpType.CONNECT)
             killConnect();
         if (task.getContext() == OpType.READ)
-            killConnect();
+            killReading();
         if (task.getContext() == OpType.WRITE)
-            killConnect();
+            killWriting();
     }
 
     // -- connect --
@@ -255,15 +238,12 @@
         }
     }
 
-    private void finishConnect(PendingFuture<Void,Object> result,
-                               boolean invokeDirect)
-    {
+    private void finishConnect(boolean mayInvokeDirect) {
         Throwable e = null;
         try {
             begin();
             checkConnect(fdVal);
             setConnected();
-            result.setResult(null);
         } catch (Throwable x) {
             if (x instanceof ClosedChannelException)
                 x = new AsynchronousCloseException();
@@ -276,26 +256,38 @@
             try {
                 close();
             } catch (IOException ignore) { }
-            result.setFailure(e);
         }
-        if (invokeDirect) {
-            Invoker.invoke(result.handler(), result);
+
+
+        // invoke handler and set result
+        CompletionHandler<Void,Object> handler = connectHandler;
+        Object att = connectAttachment;
+        PendingFuture<Void,Object> future = connectFuture;
+        if (handler == null) {
+            future.setResult(null, e);
         } else {
-            Invoker.invokeIndirectly(result.handler(), result);
+            if (mayInvokeDirect) {
+                Invoker.invokeUnchecked(handler, att, null, e);
+            } else {
+                Invoker.invokeIndirectly(this, handler, att, null, e);
+            }
         }
     }
 
     @Override
     @SuppressWarnings("unchecked")
-    public <A> Future<Void> connect(SocketAddress remote,
-                                    A attachment,
-                                    CompletionHandler<Void,? super A> handler)
+    <A> Future<Void> implConnect(SocketAddress remote,
+                                 A attachment,
+                                 CompletionHandler<Void,? super A> handler)
     {
         if (!isOpen()) {
-            CompletedFuture<Void,A> result = CompletedFuture
-                .withFailure(this, new ClosedChannelException(), attachment);
-            Invoker.invoke(handler, result);
-            return result;
+            Throwable e = new ClosedChannelException();
+            if (handler == null) {
+                return CompletedFuture.withFailure(e);
+            } else {
+                Invoker.invoke(this, handler, attachment, null, e);
+                return null;
+            }
         }
 
         InetSocketAddress isa = Net.checkAddress(remote);
@@ -317,7 +309,6 @@
             notifyBeforeTcpConnect = (localAddress == null);
         }
 
-        AbstractFuture<Void,A> result = null;
         Throwable e = null;
         try {
             begin();
@@ -327,15 +318,21 @@
             int n = Net.connect(fd, isa.getAddress(), isa.getPort());
             if (n == IOStatus.UNAVAILABLE) {
                 // connection could not be established immediately
-                result = new PendingFuture<Void,A>(this, handler, attachment, OpType.CONNECT);
+                PendingFuture<Void,A> result = null;
                 synchronized (updateLock) {
-                    this.pendingConnect = (PendingFuture<Void,Object>)result;
+                    if (handler == null) {
+                        result = new PendingFuture<Void,A>(this, OpType.CONNECT);
+                        this.connectFuture = (PendingFuture<Void,Object>)result;
+                    } else {
+                        this.connectHandler = (CompletionHandler<Void,Object>)handler;
+                        this.connectAttachment = attachment;
+                    }
+                    this.connectPending = true;
                     updateEvents();
                 }
                 return result;
             }
             setConnected();
-            result = CompletedFuture.withResult(this, null, attachment);
         } catch (Throwable x) {
             if (x instanceof ClosedChannelException)
                 x = new AsynchronousCloseException();
@@ -349,84 +346,111 @@
             try {
                 close();
             } catch (IOException ignore) { }
-            result = CompletedFuture.withFailure(this, e, attachment);
         }
-
-        Invoker.invoke(handler, result);
-        return result;
+        if (handler == null) {
+            return CompletedFuture.withResult(null, e);
+        } else {
+            Invoker.invoke(this, handler, attachment, null, e);
+            return null;
+        }
     }
 
     // -- read --
 
-    @SuppressWarnings("unchecked")
-    private void finishRead(PendingFuture<Number,Object> result,
-                            boolean invokeDirect)
-    {
+    private void finishRead(boolean mayInvokeDirect) {
         int n = -1;
-        PendingFuture<Number,Object> pending = null;
+        Throwable exc = null;
+
+        // copy fields as we can't access them after reading is re-enabled.
+        boolean scattering = isScatteringRead;
+        CompletionHandler<Number,Object> handler = readHandler;
+        Object att = readAttachment;
+        PendingFuture<Number,Object> future = readFuture;
+        Future<?> timeout = readTimer;
+
         try {
             begin();
 
-            ByteBuffer[] dsts = readBuffers;
-            if (dsts.length == 1) {
-                n = IOUtil.read(fd, dsts[0], -1, nd, null);
+            if (scattering) {
+                n = (int)IOUtil.read(fd, readBuffers, nd);
             } else {
-                n = (int)IOUtil.read(fd, dsts, nd);
+                n = IOUtil.read(fd, readBuffer, -1, nd, null);
             }
             if (n == IOStatus.UNAVAILABLE) {
                 // spurious wakeup, is this possible?
-                pending = result;
+                synchronized (updateLock) {
+                    readPending = true;
+                }
                 return;
             }
 
-            // allow buffer(s) to be GC'ed.
-            readBuffers = null;
+            // allow objects to be GC'ed.
+            this.readBuffer = null;
+            this.readBuffers = null;
+            this.readAttachment = null;
 
             // allow another read to be initiated
-            boolean wasScatteringRead = scatteringRead;
             enableReading();
 
-            // result is Integer or Long
-            if (wasScatteringRead) {
-                result.setResult(Long.valueOf(n));
-            } else {
-                result.setResult(Integer.valueOf(n));
-            }
-
         } catch (Throwable x) {
             enableReading();
             if (x instanceof ClosedChannelException)
                 x = new AsynchronousCloseException();
-            result.setFailure(x);
+            exc = x;
         } finally {
             // restart poll in case of concurrent write
             synchronized (updateLock) {
-                if (pending != null)
-                    this.pendingRead = pending;
                 updateEvents();
             }
             end();
         }
 
-        if (invokeDirect) {
-            Invoker.invoke(result.handler(), result);
+        // cancel the associated timer
+        if (timeout != null)
+            timeout.cancel(false);
+
+        // create result
+        Number result = (exc != null) ? null : (scattering) ?
+            (Number)Long.valueOf(n) : (Number)Integer.valueOf(n);
+
+        // invoke handler or set result
+        if (handler == null) {
+            future.setResult(result, exc);
         } else {
-            Invoker.invokeIndirectly(result.handler(), result);
+            if (mayInvokeDirect) {
+                Invoker.invokeUnchecked(handler, att, result, exc);
+            } else {
+                Invoker.invokeIndirectly(this, handler, att, result, exc);
+            }
         }
     }
 
     private Runnable readTimeoutTask = new Runnable() {
         public void run() {
-            PendingFuture<Number,Object> result = grabPendingRead();
-            if (result == null)
-                return;     // already completed
+            CompletionHandler<Number,Object> handler = null;
+            Object att = null;
+            PendingFuture<Number,Object> future = null;
+
+            synchronized (updateLock) {
+                if (!readPending)
+                    return;
+                readPending = false;
+                handler = readHandler;
+                att = readAttachment;
+                future = readFuture;
+            }
 
             // kill further reading before releasing waiters
             enableReading(true);
 
-            // set completed and invoke handler
-            result.setFailure(new InterruptedByTimeoutException());
-            Invoker.invokeIndirectly(result.handler(), result);
+            // invoke handler or set result
+            Exception exc = new InterruptedByTimeoutException();
+            if (handler == null) {
+                future.setFailure(exc);
+            } else {
+                AsynchronousChannel ch = UnixAsynchronousSocketChannelImpl.this;
+                Invoker.invokeIndirectly(ch, handler, att, null, exc);
+            }
         }
     };
 
@@ -435,8 +459,9 @@
      */
     @Override
     @SuppressWarnings("unchecked")
-    <V extends Number,A> Future<V> readImpl(ByteBuffer[] dsts,
-                                            boolean isScatteringRead,
+    <V extends Number,A> Future<V> implRead(boolean isScatteringRead,
+                                            ByteBuffer dst,
+                                            ByteBuffer[] dsts,
                                             long timeout,
                                             TimeUnit unit,
                                             A attachment,
@@ -450,144 +475,178 @@
         boolean invokeDirect = false;
         boolean attemptRead = false;
         if (!disableSynchronousRead) {
-            myGroupAndInvokeCount = Invoker.getGroupAndInvokeCount();
-            invokeDirect = Invoker.mayInvokeDirect(myGroupAndInvokeCount, port);
-            attemptRead = (handler == null) || invokeDirect ||
-                !port.isFixedThreadPool();  // okay to attempt read with user thread pool
+            if (handler == null) {
+                attemptRead = true;
+            } else {
+                myGroupAndInvokeCount = Invoker.getGroupAndInvokeCount();
+                invokeDirect = Invoker.mayInvokeDirect(myGroupAndInvokeCount, port);
+                // okay to attempt read with user thread pool
+                attemptRead = invokeDirect || !port.isFixedThreadPool();
+            }
         }
 
-        AbstractFuture<V,A> result;
+        int n = IOStatus.UNAVAILABLE;
+        Throwable exc = null;
+        boolean pending = false;
+
         try {
             begin();
 
-            int n;
             if (attemptRead) {
                 if (isScatteringRead) {
                     n = (int)IOUtil.read(fd, dsts, nd);
                 } else {
-                    n = IOUtil.read(fd, dsts[0], -1, nd, null);
+                    n = IOUtil.read(fd, dst, -1, nd, null);
                 }
-            } else {
-                n = IOStatus.UNAVAILABLE;
             }
 
             if (n == IOStatus.UNAVAILABLE) {
-                result = new PendingFuture<V,A>(this, handler, attachment, OpType.READ);
-
-                // update evetns so that read will complete asynchronously
+                PendingFuture<V,A> result = null;
                 synchronized (updateLock) {
+                    this.isScatteringRead = isScatteringRead;
+                    this.readBuffer = dst;
                     this.readBuffers = dsts;
-                    this.scatteringRead = isScatteringRead;
-                    this.pendingRead = (PendingFuture<Number,Object>)result;
+                    if (handler == null) {
+                        this.readHandler = null;
+                        result = new PendingFuture<V,A>(this, OpType.READ);
+                        this.readFuture = (PendingFuture<Number,Object>)result;
+                        this.readAttachment = null;
+                    } else {
+                        this.readHandler = (CompletionHandler<Number,Object>)handler;
+                        this.readAttachment = attachment;
+                        this.readFuture = null;
+                    }
+                    if (timeout > 0L) {
+                        this.readTimer = port.schedule(readTimeoutTask, timeout, unit);
+                    }
+                    this.readPending = true;
                     updateEvents();
                 }
-
-                // schedule timeout
-                if (timeout > 0L) {
-                    Future<?> timeoutTask =
-                        port.schedule(readTimeoutTask, timeout, unit);
-                    ((PendingFuture<V,A>)result).setTimeoutTask(timeoutTask);
-                }
+                pending = true;
                 return result;
             }
-
-            // data available
-            enableReading();
-
-            // result type is Long or Integer
-            if (isScatteringRead) {
-                result = (CompletedFuture<V,A>)CompletedFuture
-                    .withResult(this, Long.valueOf(n), attachment);
-            } else {
-                result = (CompletedFuture<V,A>)CompletedFuture
-                    .withResult(this, Integer.valueOf(n), attachment);
-            }
         } catch (Throwable x) {
-            enableReading();
             if (x instanceof ClosedChannelException)
                 x = new AsynchronousCloseException();
-            result = CompletedFuture.withFailure(this, x, attachment);
+            exc = x;
         } finally {
+            if (!pending)
+                enableReading();
             end();
         }
 
-        if (invokeDirect) {
-            Invoker.invokeDirect(myGroupAndInvokeCount, handler, result);
+        Number result = (exc != null) ? null : (isScatteringRead) ?
+            (Number)Long.valueOf(n) : (Number)Integer.valueOf(n);
+
+        // read completed immediately
+        if (handler != null) {
+            if (invokeDirect) {
+                Invoker.invokeDirect(myGroupAndInvokeCount, handler, attachment, (V)result, exc);
+            } else {
+                Invoker.invokeIndirectly(this, handler, attachment, (V)result, exc);
+            }
+            return null;
         } else {
-            Invoker.invokeIndirectly(handler, result);
+            return CompletedFuture.withResult((V)result, exc);
         }
-        return result;
     }
 
     // -- write --
 
-    private void finishWrite(PendingFuture<Number,Object> result,
-                             boolean invokeDirect)
-    {
-        PendingFuture<Number,Object> pending = null;
+    private void finishWrite(boolean mayInvokeDirect) {
+        int n = -1;
+        Throwable exc = null;
+
+        // copy fields as we can't access them after reading is re-enabled.
+        boolean gathering = this.isGatheringWrite;
+        CompletionHandler<Number,Object> handler = this.writeHandler;
+        Object att = this.writeAttachment;
+        PendingFuture<Number,Object> future = this.writeFuture;
+        Future<?> timer = this.writeTimer;
+
         try {
             begin();
 
-            ByteBuffer[] srcs = writeBuffers;
-            int n;
-            if (srcs.length == 1) {
-                n = IOUtil.write(fd, srcs[0], -1, nd, null);
+            if (gathering) {
+                n = (int)IOUtil.write(fd, writeBuffers, nd);
             } else {
-                n = (int)IOUtil.write(fd, srcs, nd);
+                n = IOUtil.write(fd, writeBuffer, -1, nd, null);
             }
             if (n == IOStatus.UNAVAILABLE) {
                 // spurious wakeup, is this possible?
-                pending = result;
+                synchronized (updateLock) {
+                    writePending = true;
+                }
                 return;
             }
 
-            // allow buffer(s) to be GC'ed.
-            writeBuffers = null;
+            // allow objects to be GC'ed.
+            this.writeBuffer = null;
+            this.writeBuffers = null;
+            this.writeAttachment = null;
 
             // allow another write to be initiated
-            boolean wasGatheringWrite = gatheringWrite;
             enableWriting();
 
-            // result is a Long or Integer
-            if (wasGatheringWrite) {
-                result.setResult(Long.valueOf(n));
-            } else {
-                result.setResult(Integer.valueOf(n));
-            }
-
         } catch (Throwable x) {
             enableWriting();
             if (x instanceof ClosedChannelException)
                 x = new AsynchronousCloseException();
-            result.setFailure(x);
+            exc = x;
         } finally {
-            // restart poll in case of concurrent read
-            synchronized (this) {
-                if (pending != null)
-                    this.pendingWrite = pending;
+            // restart poll in case of concurrent write
+            synchronized (updateLock) {
                 updateEvents();
             }
             end();
         }
-        if (invokeDirect) {
-            Invoker.invoke(result.handler(), result);
+
+        // cancel the associated timer
+        if (timer != null)
+            timer.cancel(false);
+
+        // create result
+        Number result = (exc != null) ? null : (gathering) ?
+            (Number)Long.valueOf(n) : (Number)Integer.valueOf(n);
+
+        // invoke handler or set result
+        if (handler == null) {
+            future.setResult(result, exc);
         } else {
-            Invoker.invokeIndirectly(result.handler(), result);
+            if (mayInvokeDirect) {
+                Invoker.invokeUnchecked(handler, att, result, exc);
+            } else {
+                Invoker.invokeIndirectly(this, handler, att, result, exc);
+            }
         }
     }
 
     private Runnable writeTimeoutTask = new Runnable() {
         public void run() {
-            PendingFuture<Number,Object> result = grabPendingWrite();
-            if (result == null)
-                return;     // already completed
+            CompletionHandler<Number,Object> handler = null;
+            Object att = null;
+            PendingFuture<Number,Object> future = null;
+
+            synchronized (updateLock) {
+                if (!writePending)
+                    return;
+                writePending = false;
+                handler = writeHandler;
+                att = writeAttachment;
+                future = writeFuture;
+            }
 
             // kill further writing before releasing waiters
             enableWriting(true);
 
-            // set completed and invoke handler
-            result.setFailure(new InterruptedByTimeoutException());
-            Invoker.invokeIndirectly(result.handler(), result);
+            // invoke handler or set result
+            Exception exc = new InterruptedByTimeoutException();
+            if (handler != null) {
+                Invoker.invokeIndirectly(UnixAsynchronousSocketChannelImpl.this,
+                    handler, att, null, exc);
+            } else {
+                future.setFailure(exc);
+            }
         }
     };
 
@@ -596,8 +655,9 @@
      */
     @Override
     @SuppressWarnings("unchecked")
-    <V extends Number,A> Future<V> writeImpl(ByteBuffer[] srcs,
-                                             boolean isGatheringWrite,
+    <V extends Number,A> Future<V> implWrite(boolean isGatheringWrite,
+                                             ByteBuffer src,
+                                             ByteBuffer[] srcs,
                                              long timeout,
                                              TimeUnit unit,
                                              A attachment,
@@ -607,66 +667,72 @@
             Invoker.getGroupAndInvokeCount();
         boolean invokeDirect = Invoker.mayInvokeDirect(myGroupAndInvokeCount, port);
         boolean attemptWrite = (handler == null) || invokeDirect ||
-            !port.isFixedThreadPool();  // okay to attempt read with user thread pool
+            !port.isFixedThreadPool();  // okay to attempt write with user thread pool
 
-        AbstractFuture<V,A> result;
+        int n = IOStatus.UNAVAILABLE;
+        Throwable exc = null;
+        boolean pending = false;
+
         try {
             begin();
 
-            int n;
             if (attemptWrite) {
                 if (isGatheringWrite) {
                     n = (int)IOUtil.write(fd, srcs, nd);
                 } else {
-                    n = IOUtil.write(fd, srcs[0], -1, nd, null);
+                    n = IOUtil.write(fd, src, -1, nd, null);
                 }
-            } else {
-                n = IOStatus.UNAVAILABLE;
             }
 
             if (n == IOStatus.UNAVAILABLE) {
-                result = new PendingFuture<V,A>(this, handler, attachment, OpType.WRITE);
-
-                // update evetns so that read will complete asynchronously
+                PendingFuture<V,A> result = null;
                 synchronized (updateLock) {
+                    this.isGatheringWrite = isGatheringWrite;
+                    this.writeBuffer = src;
                     this.writeBuffers = srcs;
-                    this.gatheringWrite = isGatheringWrite;
-                    this.pendingWrite = (PendingFuture<Number,Object>)result;
+                    if (handler == null) {
+                        this.writeHandler = null;
+                        result = new PendingFuture<V,A>(this, OpType.WRITE);
+                        this.writeFuture = (PendingFuture<Number,Object>)result;
+                        this.writeAttachment = null;
+                    } else {
+                        this.writeHandler = (CompletionHandler<Number,Object>)handler;
+                        this.writeAttachment = attachment;
+                        this.writeFuture = null;
+                    }
+                    if (timeout > 0L) {
+                        this.writeTimer = port.schedule(writeTimeoutTask, timeout, unit);
+                    }
+                    this.writePending = true;
                     updateEvents();
                 }
-
-                // schedule timeout
-                if (timeout > 0L) {
-                    Future<?> timeoutTask =
-                        port.schedule(writeTimeoutTask, timeout, unit);
-                    ((PendingFuture<V,A>)result).setTimeoutTask(timeoutTask);
-                }
+                pending = true;
                 return result;
             }
-
-            // data available
-            enableWriting();
-            if (isGatheringWrite) {
-                result = (CompletedFuture<V,A>)CompletedFuture
-                    .withResult(this, Long.valueOf(n), attachment);
-            } else {
-                result = (CompletedFuture<V,A>)CompletedFuture
-                    .withResult(this, Integer.valueOf(n), attachment);
-            }
         } catch (Throwable x) {
-            enableWriting();
             if (x instanceof ClosedChannelException)
                 x = new AsynchronousCloseException();
-            result = CompletedFuture.withFailure(this, x, attachment);
+            exc = x;
         } finally {
+            if (!pending)
+                enableWriting();
             end();
         }
-        if (invokeDirect) {
-            Invoker.invokeDirect(myGroupAndInvokeCount, handler, result);
+
+        Number result = (exc != null) ? null : (isGatheringWrite) ?
+            (Number)Long.valueOf(n) : (Number)Integer.valueOf(n);
+
+        // write completed immediately
+        if (handler != null) {
+            if (invokeDirect) {
+                Invoker.invokeDirect(myGroupAndInvokeCount, handler, attachment, (V)result, exc);
+            } else {
+                Invoker.invokeIndirectly(this, handler, attachment, (V)result, exc);
+            }
+            return null;
         } else {
-            Invoker.invokeIndirectly(handler, result);
+            return CompletedFuture.withResult((V)result, exc);
         }
-        return result;
     }
 
     // -- Native methods --
--- a/src/windows/classes/sun/nio/ch/Iocp.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/windows/classes/sun/nio/ch/Iocp.java	Sun Aug 23 12:53:45 2009 +0100
@@ -34,6 +34,8 @@
 import java.util.concurrent.*;
 import java.util.concurrent.locks.ReadWriteLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
+import java.security.AccessController;
+import sun.security.action.GetPropertyAction;
 import sun.misc.Unsafe;
 
 /**
@@ -44,6 +46,7 @@
 class Iocp extends AsynchronousChannelGroupImpl {
     private static final Unsafe unsafe = Unsafe.getUnsafe();
     private static final long INVALID_HANDLE_VALUE  = -1L;
+    private static final boolean supportsThreadAgnosticIo;
 
     // maps completion key to channel
     private final ReadWriteLock keyToChannelLock = new ReentrantReadWriteLock();
@@ -87,6 +90,13 @@
         <V,A> PendingFuture<V,A> getByOverlapped(long overlapped);
     }
 
+    /**
+     * Indicates if this operating system supports thread agnostic I/O.
+     */
+    static boolean supportsThreadAgnosticIo() {
+        return supportsThreadAgnosticIo;
+    }
+
     // release all resources
     void implClose() {
         synchronized (this) {
@@ -216,8 +226,9 @@
             } while ((key == 0) || keyToChannel.containsKey(key));
 
             // associate with I/O completion port
-            if (handle != 0L)
+            if (handle != 0L) {
                 createIoCompletionPort(handle, port, key, 0);
+            }
 
             // setup mapping
             keyToChannel.put(key, ch);
@@ -282,7 +293,7 @@
         /**
          * Invoked if the I/O operation completes successfully.
          */
-        public void completed(int bytesTransferred);
+        public void completed(int bytesTransferred, boolean canInvokeDirect);
 
         /**
          * Invoked if the I/O operation fails.
@@ -305,6 +316,7 @@
         public void run() {
             Invoker.GroupAndInvokeCount myGroupAndInvokeCount =
                 Invoker.getGroupAndInvokeCount();
+            boolean canInvokeDirect = (myGroupAndInvokeCount != null);
             CompletionStatus ioResult = new CompletionStatus();
             boolean replaceMe = false;
 
@@ -382,7 +394,7 @@
                     ResultHandler rh = (ResultHandler)result.getContext();
                     replaceMe = true; // (if error/exception then replace thread)
                     if (error == 0) {
-                        rh.completed(ioResult.bytesTransferred());
+                        rh.completed(ioResult.bytesTransferred(), canInvokeDirect);
                     } else {
                         rh.failed(error, translateErrorToIOException(error));
                     }
@@ -433,5 +445,11 @@
     static {
         Util.load();
         initIDs();
+
+        // thread agnostic I/O on Vista/2008 or newer
+        String osversion = AccessController.doPrivileged(
+            new GetPropertyAction("os.version"));
+        String vers[] = osversion.split("\\.");
+        supportsThreadAgnosticIo = Integer.parseInt(vers[0]) >= 6;
     }
 }
--- a/src/windows/classes/sun/nio/ch/WindowsAsynchronousFileChannelImpl.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/windows/classes/sun/nio/ch/WindowsAsynchronousFileChannelImpl.java	Sun Aug 23 12:53:45 2009 +0100
@@ -146,10 +146,12 @@
         // waits until all I/O operations have completed
         ioCache.close();
 
-        // disassociate from port and shutdown thread pool if not default
+        // disassociate from port
         iocp.disassociate(completionKey);
+
+        // for the non-default group close the port
         if (!isDefaultIocp)
-            iocp.shutdown();
+            iocp.detachFromThreadPool();
     }
 
     @Override
@@ -258,14 +260,18 @@
             }
 
             // invoke completion handler
-            Invoker.invoke(result.handler(), result);
+            Invoker.invoke(result);
         }
 
         @Override
-        public void completed(int bytesTransferred) {
+        public void completed(int bytesTransferred, boolean canInvokeDirect) {
             // release waiters and invoke completion handler
             result.setResult(fli);
-            Invoker.invoke(result.handler(), result);
+            if (canInvokeDirect) {
+                Invoker.invokeUnchecked(result);
+            } else {
+                Invoker.invoke(result);
+            }
         }
 
         @Override
@@ -279,16 +285,16 @@
             } else {
                 result.setFailure(new AsynchronousCloseException());
             }
-            Invoker.invoke(result.handler(), result);
+            Invoker.invoke(result);
         }
     }
 
     @Override
-    public <A> Future<FileLock> lock(long position,
-                                     long size,
-                                     boolean shared,
-                                     A attachment,
-                                     CompletionHandler<FileLock,? super A> handler)
+    <A> Future<FileLock> implLock(final long position,
+                                  final long size,
+                                  final boolean shared,
+                                  A attachment,
+                                  final CompletionHandler<FileLock,? super A> handler)
     {
         if (shared && !reading)
             throw new NonReadableChannelException();
@@ -298,10 +304,11 @@
         // add to lock table
         FileLockImpl fli = addToFileLockTable(position, size, shared);
         if (fli == null) {
-            CompletedFuture<FileLock,A> result = CompletedFuture
-                .withFailure(this, new ClosedChannelException(), attachment);
-            Invoker.invoke(handler, result);
-            return result;
+            Throwable exc = new ClosedChannelException();
+            if (handler == null)
+                return CompletedFuture.withFailure(exc);
+            Invoker.invoke(this, handler, attachment, null, exc);
+            return null;
         }
 
         // create Future and task that will be invoked to acquire lock
@@ -310,13 +317,20 @@
         LockTask lockTask = new LockTask<A>(position, fli, result);
         result.setContext(lockTask);
 
-        // initiate I/O (can only be done from thread in thread pool)
-        try {
-            Invoker.invokeOnThreadInThreadPool(this, lockTask);
-        } catch (ShutdownChannelGroupException e) {
-            // rollback
-            removeFromFileLockTable(fli);
-            throw e;
+        // initiate I/O
+        if (Iocp.supportsThreadAgnosticIo()) {
+            lockTask.run();
+        } else {
+            boolean executed = false;
+            try {
+                Invoker.invokeOnThreadInThreadPool(this, lockTask);
+                executed = true;
+            } finally {
+                if (!executed) {
+                    // rollback
+                    removeFromFileLockTable(fli);
+                }
+            }
         }
         return result;
     }
@@ -461,14 +475,14 @@
             releaseBufferIfSubstituted();
 
             // invoke completion handler
-            Invoker.invoke(result.handler(), result);
+            Invoker.invoke(result);
         }
 
         /**
          * Executed when the I/O has completed
          */
         @Override
-        public void completed(int bytesTransferred) {
+        public void completed(int bytesTransferred, boolean canInvokeDirect) {
             updatePosition(bytesTransferred);
 
             // return direct buffer to cache if substituted
@@ -476,14 +490,18 @@
 
             // release waiters and invoke completion handler
             result.setResult(bytesTransferred);
-            Invoker.invoke(result.handler(), result);
+            if (canInvokeDirect) {
+                Invoker.invokeUnchecked(result);
+            } else {
+                Invoker.invoke(result);
+            }
         }
 
         @Override
         public void failed(int error, IOException x) {
             // if EOF detected asynchronously then it is reported as error
             if (error == ERROR_HANDLE_EOF) {
-                completed(-1);
+                completed(-1, false);
             } else {
                 // return direct buffer to cache if substituted
                 releaseBufferIfSubstituted();
@@ -494,16 +512,16 @@
                 } else {
                     result.setFailure(new AsynchronousCloseException());
                 }
-                Invoker.invoke(result.handler(), result);
+                Invoker.invoke(result);
             }
         }
     }
 
     @Override
-    public <A> Future<Integer> read(ByteBuffer dst,
-                                    long position,
-                                    A attachment,
-                                    CompletionHandler<Integer,? super A> handler)
+    <A> Future<Integer> implRead(ByteBuffer dst,
+                                 long position,
+                                 A attachment,
+                                 CompletionHandler<Integer,? super A> handler)
     {
         if (!reading)
             throw new NonReadableChannelException();
@@ -514,10 +532,11 @@
 
         // check if channel is closed
         if (!isOpen()) {
-            CompletedFuture<Integer,A> result = CompletedFuture
-                .withFailure(this, new ClosedChannelException(), attachment);
-            Invoker.invoke(handler, result);
-            return result;
+            Throwable exc = new ClosedChannelException();
+            if (handler == null)
+                return CompletedFuture.withFailure(exc);
+            Invoker.invoke(this, handler, attachment, null, exc);
+            return null;
         }
 
         int pos = dst.position();
@@ -527,10 +546,10 @@
 
         // no space remaining
         if (rem == 0) {
-            CompletedFuture<Integer,A> result =
-                CompletedFuture.withResult(this, 0, attachment);
-            Invoker.invoke(handler, result);
-            return result;
+            if (handler == null)
+                return CompletedFuture.withResult(0);
+            Invoker.invoke(this, handler, attachment, 0, null);
+            return null;
         }
 
         // create Future and task that initiates read
@@ -539,8 +558,12 @@
         ReadTask readTask = new ReadTask<A>(dst, pos, rem, position, result);
         result.setContext(readTask);
 
-        // initiate I/O (can only be done from thread in thread pool)
-        Invoker.invokeOnThreadInThreadPool(this, readTask);
+        // initiate I/O
+        if (Iocp.supportsThreadAgnosticIo()) {
+            readTask.run();
+        } else {
+            Invoker.invokeOnThreadInThreadPool(this, readTask);
+        }
         return result;
     }
 
@@ -639,14 +662,14 @@
             }
 
             // invoke completion handler
-            Invoker.invoke(result.handler(), result);
+            Invoker.invoke(result);
         }
 
         /**
          * Executed when the I/O has completed
          */
         @Override
-        public void completed(int bytesTransferred) {
+        public void completed(int bytesTransferred, boolean canInvokeDirect) {
             updatePosition(bytesTransferred);
 
             // return direct buffer to cache if substituted
@@ -654,7 +677,11 @@
 
             // release waiters and invoke completion handler
             result.setResult(bytesTransferred);
-            Invoker.invoke(result.handler(), result);
+            if (canInvokeDirect) {
+                Invoker.invokeUnchecked(result);
+            } else {
+                Invoker.invoke(result);
+            }
         }
 
         @Override
@@ -668,15 +695,14 @@
             } else {
                 result.setFailure(new AsynchronousCloseException());
             }
-            Invoker.invoke(result.handler(), result);
+            Invoker.invoke(result);
         }
     }
 
-    @Override
-    public <A> Future<Integer> write(ByteBuffer src,
-                                     long position,
-                                     A attachment,
-                                     CompletionHandler<Integer,? super A> handler)
+    <A> Future<Integer> implWrite(ByteBuffer src,
+                                  long position,
+                                  A attachment,
+                                  CompletionHandler<Integer,? super A> handler)
     {
         if (!writing)
             throw new NonWritableChannelException();
@@ -685,10 +711,11 @@
 
         // check if channel is closed
         if (!isOpen()) {
-            CompletedFuture<Integer,A> result = CompletedFuture
-                .withFailure(this, new ClosedChannelException(), attachment);
-            Invoker.invoke(handler, result);
-            return result;
+           Throwable exc = new ClosedChannelException();
+            if (handler == null)
+                return CompletedFuture.withFailure(exc);
+            Invoker.invoke(this, handler, attachment, null, exc);
+            return null;
         }
 
         int pos = src.position();
@@ -698,10 +725,10 @@
 
         // nothing to write
         if (rem == 0) {
-            CompletedFuture<Integer,A> result =
-                CompletedFuture.withResult(this, 0, attachment);
-            Invoker.invoke(handler, result);
-            return result;
+            if (handler == null)
+                return CompletedFuture.withResult(0);
+            Invoker.invoke(this, handler, attachment, 0, null);
+            return null;
         }
 
         // create Future and task to initiate write
@@ -710,8 +737,12 @@
         WriteTask writeTask = new WriteTask<A>(src, pos, rem, position, result);
         result.setContext(writeTask);
 
-        // initiate I/O (can only be done from thread in thread pool)
-        Invoker.invokeOnThreadInThreadPool(this, writeTask);
+        // initiate I/O
+        if (Iocp.supportsThreadAgnosticIo()) {
+            writeTask.run();
+        } else {
+            Invoker.invokeOnThreadInThreadPool(this, writeTask);
+        }
         return result;
     }
 
--- a/src/windows/classes/sun/nio/ch/WindowsAsynchronousServerSocketChannelImpl.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/windows/classes/sun/nio/ch/WindowsAsynchronousServerSocketChannelImpl.java	Sun Aug 23 12:53:45 2009 +0100
@@ -113,14 +113,14 @@
     /**
      * Task to initiate accept operation and to handle result.
      */
-    private class AcceptTask<A> implements Runnable, Iocp.ResultHandler {
+    private class AcceptTask implements Runnable, Iocp.ResultHandler {
         private final WindowsAsynchronousSocketChannelImpl channel;
         private final AccessControlContext acc;
-        private final PendingFuture<AsynchronousSocketChannel,A> result;
+        private final PendingFuture<AsynchronousSocketChannel,Object> result;
 
         AcceptTask(WindowsAsynchronousSocketChannelImpl channel,
                    AccessControlContext acc,
-                   PendingFuture<AsynchronousSocketChannel,A> result)
+                   PendingFuture<AsynchronousSocketChannel,Object> result)
         {
             this.channel = channel;
             this.acc = acc;
@@ -222,14 +222,14 @@
             }
 
             // invoke completion handler
-            Invoker.invokeIndirectly(result.handler(), result);
+            Invoker.invokeIndirectly(result);
         }
 
         /**
          * Executed when the I/O has completed
          */
         @Override
-        public void completed(int bytesTransferred) {
+        public void completed(int bytesTransferred, boolean canInvokeDirect) {
             try {
                 // connection accept after group has shutdown
                 if (iocp.isShutdown()) {
@@ -269,7 +269,7 @@
             }
 
             // invoke handler (but not directly)
-            Invoker.invokeIndirectly(result.handler(), result);
+            Invoker.invokeIndirectly(result);
         }
 
         @Override
@@ -283,19 +283,20 @@
             } else {
                 result.setFailure(new AsynchronousCloseException());
             }
-            Invoker.invokeIndirectly(result.handler(), result);
+            Invoker.invokeIndirectly(result);
         }
     }
 
     @Override
-    public <A> Future<AsynchronousSocketChannel> accept(A attachment,
-        final CompletionHandler<AsynchronousSocketChannel,? super A> handler)
+    Future<AsynchronousSocketChannel> implAccept(Object attachment,
+        final CompletionHandler<AsynchronousSocketChannel,Object> handler)
     {
         if (!isOpen()) {
-            CompletedFuture<AsynchronousSocketChannel,A> result = CompletedFuture
-                .withFailure(this, new ClosedChannelException(), attachment);
-            Invoker.invokeIndirectly(handler, result);
-            return result;
+            Throwable exc = new ClosedChannelException();
+            if (handler == null)
+                return CompletedFuture.withFailure(exc);
+            Invoker.invokeIndirectly(this, handler, attachment, null, exc);
+            return null;
         }
         if (isAcceptKilled())
             throw new RuntimeException("Accept not allowed due to cancellation");
@@ -319,10 +320,10 @@
             end();
         }
         if (ioe != null) {
-            CompletedFuture<AsynchronousSocketChannel,A> result =
-                CompletedFuture.withFailure(this, ioe, attachment);
-            Invoker.invokeIndirectly(handler, result);
-            return result;
+            if (handler == null)
+                return CompletedFuture.withFailure(ioe);
+            Invoker.invokeIndirectly(this, handler, attachment, null, ioe);
+            return null;
         }
 
         // need calling context when there is security manager as
@@ -331,20 +332,21 @@
         AccessControlContext acc = (System.getSecurityManager() == null) ?
             null : AccessController.getContext();
 
-        PendingFuture<AsynchronousSocketChannel,A> result =
-            new PendingFuture<AsynchronousSocketChannel,A>(this, handler, attachment);
-        AcceptTask task = new AcceptTask<A>(ch, acc, result);
+        PendingFuture<AsynchronousSocketChannel,Object> result =
+            new PendingFuture<AsynchronousSocketChannel,Object>(this, handler, attachment);
+        AcceptTask task = new AcceptTask(ch, acc, result);
         result.setContext(task);
 
         // check and set flag to prevent concurrent accepting
         if (!accepting.compareAndSet(false, true))
             throw new AcceptPendingException();
 
-        // initiate accept. As I/O operations are tied to the initiating thread
-        // then it will only be invoked direcly if this thread is in the thread
-        // pool. If this thread is not in the thread pool when a task is
-        // submitted to initiate the accept.
-        Invoker.invokeOnThreadInThreadPool(this, task);
+        // initiate I/O
+        if (Iocp.supportsThreadAgnosticIo()) {
+            task.run();
+        } else {
+            Invoker.invokeOnThreadInThreadPool(this, task);
+        }
         return result;
     }
 
--- a/src/windows/classes/sun/nio/ch/WindowsAsynchronousSocketChannelImpl.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/windows/classes/sun/nio/ch/WindowsAsynchronousSocketChannelImpl.java	Sun Aug 23 12:53:45 2009 +0100
@@ -250,14 +250,14 @@
                 closeChannel();
                 result.setFailure(toIOException(exc));
             }
-            Invoker.invoke(result.handler(), result);
+            Invoker.invoke(result);
         }
 
         /**
          * Invoked by handler thread when connection established.
          */
         @Override
-        public void completed(int bytesTransferred) {
+        public void completed(int bytesTransferred, boolean canInvokeDirect) {
             Throwable exc = null;
             try {
                 begin();
@@ -276,7 +276,11 @@
                 result.setFailure(toIOException(exc));
             }
 
-            Invoker.invoke(result.handler(), result);
+            if (canInvokeDirect) {
+                Invoker.invokeUnchecked(result);
+            } else {
+                Invoker.invoke(result);
+            }
         }
 
         /**
@@ -290,20 +294,21 @@
             } else {
                 result.setFailure(new AsynchronousCloseException());
             }
-            Invoker.invoke(result.handler(), result);
+            Invoker.invoke(result);
         }
     }
 
     @Override
-    public <A> Future<Void> connect(SocketAddress remote,
-                                    A attachment,
-                                    CompletionHandler<Void,? super A> handler)
+    <A> Future<Void> implConnect(SocketAddress remote,
+                                 A attachment,
+                                 CompletionHandler<Void,? super A> handler)
     {
         if (!isOpen()) {
-            CompletedFuture<Void,A> result = CompletedFuture
-                .withFailure(this, new ClosedChannelException(), attachment);
-            Invoker.invoke(handler, result);
-            return result;
+            Throwable exc = new ClosedChannelException();
+            if (handler == null)
+                return CompletedFuture.withFailure(exc);
+            Invoker.invoke(this, handler, attachment, null, exc);
+            return null;
         }
 
         InetSocketAddress isa = Net.checkAddress(remote);
@@ -337,10 +342,10 @@
             try {
                 close();
             } catch (IOException ignore) { }
-            CompletedFuture<Void,A> result = CompletedFuture
-                .withFailure(this, bindException, attachment);
-            Invoker.invoke(handler, result);
-            return result;
+            if (handler == null)
+                return CompletedFuture.withFailure(bindException);
+            Invoker.invoke(this, handler, attachment, null, bindException);
+            return null;
         }
 
         // setup task
@@ -349,8 +354,12 @@
         ConnectTask task = new ConnectTask<A>(isa, result);
         result.setContext(task);
 
-        // initiate I/O (can only be done from thread in thread pool)
-        Invoker.invokeOnThreadInThreadPool(this, task);
+        // initiate I/O
+        if (Iocp.supportsThreadAgnosticIo()) {
+            task.run();
+        } else {
+            Invoker.invokeOnThreadInThreadPool(this, task);
+        }
         return result;
     }
 
@@ -514,7 +523,7 @@
             }
 
             // invoke completion handler
-            Invoker.invoke(result.handler(), result);
+            Invoker.invoke(result);
         }
 
         /**
@@ -522,7 +531,7 @@
          */
         @Override
         @SuppressWarnings("unchecked")
-        public void completed(int bytesTransferred) {
+        public void completed(int bytesTransferred, boolean canInvokeDirect) {
             if (bytesTransferred == 0) {
                 bytesTransferred = -1;  // EOF
             } else {
@@ -543,7 +552,11 @@
                     result.setResult((V)Integer.valueOf(bytesTransferred));
                 }
             }
-            Invoker.invoke(result.handler(), result);
+            if (canInvokeDirect) {
+                Invoker.invokeUnchecked(result);
+            } else {
+                Invoker.invoke(result);
+            }
         }
 
         @Override
@@ -561,7 +574,7 @@
                 enableReading();
                 result.setFailure(x);
             }
-            Invoker.invoke(result.handler(), result);
+            Invoker.invoke(result);
         }
 
         /**
@@ -579,13 +592,14 @@
             }
 
             // invoke handler without any locks
-            Invoker.invoke(result.handler(), result);
+            Invoker.invoke(result);
         }
     }
 
     @Override
-    <V extends Number,A> Future<V> readImpl(ByteBuffer[] bufs,
-                                            boolean scatteringRead,
+    <V extends Number,A> Future<V> implRead(boolean isScatteringRead,
+                                            ByteBuffer dst,
+                                            ByteBuffer[] dsts,
                                             long timeout,
                                             TimeUnit unit,
                                             A attachment,
@@ -594,7 +608,14 @@
         // setup task
         PendingFuture<V,A> result =
             new PendingFuture<V,A>(this, handler, attachment);
-        final ReadTask readTask = new ReadTask<V,A>(bufs, scatteringRead, result);
+        ByteBuffer[] bufs;
+        if (isScatteringRead) {
+            bufs = dsts;
+        } else {
+            bufs = new ByteBuffer[1];
+            bufs[0] = dst;
+        }
+        final ReadTask readTask = new ReadTask<V,A>(bufs, isScatteringRead, result);
         result.setContext(readTask);
 
         // schedule timeout
@@ -607,8 +628,12 @@
             result.setTimeoutTask(timeoutTask);
         }
 
-        // initiate I/O (can only be done from thread in thread pool)
-        Invoker.invokeOnThreadInThreadPool(this, readTask);
+        // initiate I/O
+        if (Iocp.supportsThreadAgnosticIo()) {
+            readTask.run();
+        } else {
+            Invoker.invokeOnThreadInThreadPool(this, readTask);
+        }
         return result;
     }
 
@@ -710,7 +735,7 @@
         }
 
         @Override
-        @SuppressWarnings("unchecked")
+        //@SuppressWarnings("unchecked")
         public void run() {
             long overlapped = 0L;
             boolean prepared = false;
@@ -759,7 +784,7 @@
             }
 
             // invoke completion handler
-            Invoker.invoke(result.handler(), result);
+            Invoker.invoke(result);
         }
 
         /**
@@ -767,7 +792,7 @@
          */
         @Override
         @SuppressWarnings("unchecked")
-        public void completed(int bytesTransferred) {
+        public void completed(int bytesTransferred, boolean canInvokeDirect) {
             updateBuffers(bytesTransferred);
 
             // return direct buffer to cache if substituted
@@ -784,7 +809,11 @@
                     result.setResult((V)Integer.valueOf(bytesTransferred));
                 }
             }
-            Invoker.invoke(result.handler(), result);
+            if (canInvokeDirect) {
+                Invoker.invokeUnchecked(result);
+            } else {
+                Invoker.invoke(result);
+            }
         }
 
         @Override
@@ -802,7 +831,7 @@
                 enableWriting();
                 result.setFailure(x);
             }
-            Invoker.invoke(result.handler(), result);
+            Invoker.invoke(result);
         }
 
         /**
@@ -820,13 +849,14 @@
             }
 
             // invoke handler without any locks
-            Invoker.invoke(result.handler(), result);
+            Invoker.invoke(result);
         }
     }
 
     @Override
-    <V extends Number,A> Future<V> writeImpl(ByteBuffer[] bufs,
-                                             boolean gatheringWrite,
+    <V extends Number,A> Future<V> implWrite(boolean gatheringWrite,
+                                             ByteBuffer src,
+                                             ByteBuffer[] srcs,
                                              long timeout,
                                              TimeUnit unit,
                                              A attachment,
@@ -835,6 +865,13 @@
         // setup task
         PendingFuture<V,A> result =
             new PendingFuture<V,A>(this, handler, attachment);
+        ByteBuffer[] bufs;
+        if (gatheringWrite) {
+            bufs = srcs;
+        } else {
+            bufs = new ByteBuffer[1];
+            bufs[0] = src;
+        }
         final WriteTask writeTask = new WriteTask<V,A>(bufs, gatheringWrite, result);
         result.setContext(writeTask);
 
@@ -849,7 +886,12 @@
         }
 
         // initiate I/O (can only be done from thread in thread pool)
-        Invoker.invokeOnThreadInThreadPool(this, writeTask);
+        // initiate I/O
+        if (Iocp.supportsThreadAgnosticIo()) {
+            writeTask.run();
+        } else {
+            Invoker.invokeOnThreadInThreadPool(this, writeTask);
+        }
         return result;
     }
 
--- a/src/windows/native/sun/nio/ch/Iocp.c	Sat Aug 22 17:40:18 2009 +0100
+++ b/src/windows/native/sun/nio/ch/Iocp.c	Sun Aug 23 12:53:45 2009 +0100
@@ -58,6 +58,16 @@
     completionStatus_overlapped = (*env)->GetFieldID(env, clazz, "overlapped", "J");
 }
 
+JNIEXPORT jint JNICALL
+Java_sun_nio_ch_Iocp_osMajorVersion(JNIEnv* env, jclass this)
+{
+    OSVERSIONINFOEX ver;
+    ver.dwOSVersionInfoSize = sizeof(ver);
+    GetVersionEx((OSVERSIONINFO *) &ver);
+    return (ver.dwPlatformId == VER_PLATFORM_WIN32_NT) ?
+        (jint)(ver.dwMajorVersion) : (jint)0;
+}
+
 JNIEXPORT jlong JNICALL
 Java_sun_nio_ch_Iocp_createIoCompletionPort(JNIEnv* env, jclass this,
     jlong handle, jlong existingPort, jint completionKey, jint concurrency)
--- a/test/java/nio/channels/AsynchronousChannelGroup/GroupOfOne.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/test/java/nio/channels/AsynchronousChannelGroup/GroupOfOne.java	Sun Aug 23 12:53:45 2009 +0100
@@ -22,7 +22,7 @@
  */
 
 /* @test
- * @bug 4607272
+ * @bug 4607272 6842687
  * @summary Unit test for AsynchronousChannelGroup
  */
 
@@ -50,8 +50,6 @@
             }
             public void failed(Throwable exc, Void att) {
             }
-            public void cancelled(Void att) {
-            }
         });
 
         int port = ((InetSocketAddress)(listener.getLocalAddress())).getPort();
@@ -97,9 +95,6 @@
                         System.out.println("Read failed (expected)");
                         latch.countDown();
                     }
-                    public void cancelled(Void att) {
-                        throw new RuntimeException();
-                    }
                 });
 
                 // close channel or shutdown group
@@ -122,9 +117,6 @@
             public void failed(Throwable exc, Void att) {
                 throw new RuntimeException(exc);
             }
-            public void cancelled(Void att) {
-                throw new RuntimeException();
-            }
         });
 
         latch.await();
--- a/test/java/nio/channels/AsynchronousChannelGroup/Identity.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/test/java/nio/channels/AsynchronousChannelGroup/Identity.java	Sun Aug 23 12:53:45 2009 +0100
@@ -22,7 +22,7 @@
  */
 
 /* @test
- * @bug 4607272
+ * @bug 4607272 6842687
  * @summary Unit test for AsynchronousChannelGroup
  */
 
@@ -90,14 +90,10 @@
                     }
                     public void failed(Throwable exc, Void att) {
                     }
-                    public void cancelled(Void att) {
-                    }
                 });
             }
             public void failed(Throwable exc, Void att) {
             }
-            public void cancelled(Void att) {
-            }
         });
         int port = ((InetSocketAddress)(listener.getLocalAddress())).getPort();
         SocketAddress sa = new InetSocketAddress(InetAddress.getLocalHost(), port);
@@ -141,9 +137,6 @@
             public void failed(Throwable exc, Integer groupId) {
                 fail(exc.getMessage());
             }
-            public void cancelled(Integer groupId) {
-                fail("I/O operation was cancelled");
-            }
         });
 
         // wait until
--- a/test/java/nio/channels/AsynchronousChannelGroup/Restart.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/test/java/nio/channels/AsynchronousChannelGroup/Restart.java	Sun Aug 23 12:53:45 2009 +0100
@@ -22,7 +22,7 @@
  */
 
 /* @test
- * @bug 4607272
+ * @bug 4607272 6842687
  * @summary Unit test for AsynchronousChannelGroup
  * @build Restart
  * @run main/othervm -XX:-UseVMInterruptibleIO Restart
@@ -111,8 +111,6 @@
                 }
                 public void failed(Throwable exc, Void att) {
                 }
-                public void cancelled(Void att) {
-                }
             });
 
             // establish loopback connection which should cause completion
--- a/test/java/nio/channels/AsynchronousChannelGroup/Unbounded.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/test/java/nio/channels/AsynchronousChannelGroup/Unbounded.java	Sun Aug 23 12:53:45 2009 +0100
@@ -22,7 +22,7 @@
  */
 
 /* @test
- * @bug 4607272
+ * @bug 4607272 6842687
  * @summary Unit test for AsynchronousChannelGroup
  */
 
@@ -52,8 +52,6 @@
             }
             public void failed(Throwable exc, Void att) {
             }
-            public void cancelled(Void att) {
-            }
         });
         System.out.println("Listener created.");
 
@@ -97,8 +95,6 @@
                     }
                     public void failed(Throwable exc, AsynchronousSocketChannel ch) {
                     }
-                    public void cancelled(AsynchronousSocketChannel ch) {
-                    }
                 });
         }
         System.out.println("All read operations outstanding.");
--- a/test/java/nio/channels/AsynchronousDatagramChannel/Basic.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/test/java/nio/channels/AsynchronousDatagramChannel/Basic.java	Sun Aug 23 12:53:45 2009 +0100
@@ -22,7 +22,7 @@
  */
 
 /* @test
- * @bug 4527345
+ * @bug 4527345 6842687
  * @summary Unit test for AsynchronousDatagramChannel
  */
 
@@ -72,8 +72,6 @@
             }
             public void failed (Throwable exc, Void att) {
             }
-            public void cancelled(Void att) {
-            }
         });
         Thread.sleep(2000);
         sender.send(ByteBuffer.wrap(msg), sa);
@@ -88,8 +86,6 @@
             public void failed (Throwable exc, Void att) {
                 exception.set(exc);
             }
-            public void cancelled(Void att) {
-            }
         });
         Throwable result;
         while ((result = exception.get()) == null) {
@@ -107,8 +103,6 @@
             public void failed (Throwable exc, Void att) {
                 exception.set(exc);
             }
-            public void cancelled(Void att) {
-            }
         });
         ch.close();
         while ((result = exception.get()) == null) {
@@ -162,8 +156,6 @@
             }
             public void failed (Throwable exc, Void att) {
             }
-            public void cancelled(Void att) {
-            }
         });
         Thread.sleep(2000);
         sender.send(ByteBuffer.wrap(msg), sa);
@@ -178,8 +170,6 @@
             public void failed (Throwable exc, Void att) {
                 exception.set(exc);
             }
-            public void cancelled(Void att) {
-            }
         });
         Throwable result;
         while ((result = exception.get()) == null) {
@@ -197,8 +187,6 @@
             public void failed (Throwable exc, Void att) {
                 exception.set(exc);
             }
-            public void cancelled(Void att) {
-            }
         });
         ch.close();
         while ((result = exception.get()) == null) {
@@ -246,8 +234,6 @@
             }
             public void failed (Throwable exc, Void att) {
             }
-            public void cancelled(Void att) {
-            }
         });
         l2.await(5, TimeUnit.SECONDS);
 
@@ -272,8 +258,6 @@
                     throw new RuntimeException(exc);
                 }
             }
-            public void cancelled(Void att) {
-            }
         });
         l3.await(5, TimeUnit.SECONDS);
 
@@ -323,8 +307,6 @@
             }
             public void failed (Throwable exc, Void att) {
             }
-            public void cancelled(Void att) {
-            }
         });
         l2.await(5, TimeUnit.SECONDS);
 
@@ -340,7 +322,7 @@
         reader.close();
     }
 
-    static void cancelAndCheck(Future<?> result, CountDownLatch latch)
+    static void cancelAndCheck(Future<?> result)
         throws InterruptedException
     {
         boolean cancelled = result.cancel(false);
@@ -356,37 +338,22 @@
         } catch (ExecutionException e) {
             throw new RuntimeException("Should not fail");
         }
-
-        // make sure that completion handler is invoked
-        latch.await();
     }
 
     // basic cancel tests
     static void doCancelTests() throws Exception {
         InetAddress lh = InetAddress.getLocalHost();
 
-        // timed and non-timed receive
+        // receive
         for (int i=0; i<2; i++) {
             AsynchronousDatagramChannel ch =
                 AsynchronousDatagramChannel.open().bind(new InetSocketAddress(0));
-            final CountDownLatch latch = new CountDownLatch(1);
-            long timeout = (i == 0) ? 0L : 60L;
-            Future<SocketAddress> remote = ch
-                .receive(ByteBuffer.allocate(100), timeout, TimeUnit.SECONDS, (Void)null,
-                    new CompletionHandler<SocketAddress,Void>() {
-                        public void completed(SocketAddress source, Void att) {
-                        }
-                        public void failed (Throwable exc, Void att) {
-                        }
-                        public void cancelled(Void att) {
-                            latch.countDown();
-                        }
-                    });
-            cancelAndCheck(remote, latch);
+            Future<SocketAddress> remote = ch.receive(ByteBuffer.allocate(100));
+            cancelAndCheck(remote);
             ch.close();
         }
 
-        // timed and non-timed read
+        // read
         for (int i=0; i<2; i++) {
             AsynchronousDatagramChannel ch =
                 AsynchronousDatagramChannel.open().bind(new InetSocketAddress(0));
@@ -394,18 +361,8 @@
                 ((InetSocketAddress)(ch.getLocalAddress())).getPort()));
             final CountDownLatch latch = new CountDownLatch(1);
             long timeout = (i == 0) ? 0L : 60L;
-            Future<Integer> result = ch
-                .read(ByteBuffer.allocate(100), timeout, TimeUnit.SECONDS, (Void)null,
-                    new CompletionHandler<Integer,Void>() {
-                        public void completed(Integer bytesRead, Void att) {
-                        }
-                        public void failed (Throwable exc, Void att) {
-                        }
-                        public void cancelled(Void att) {
-                            latch.countDown();
-                        }
-                    });
-            cancelAndCheck(result, latch);
+            Future<Integer> result = ch.read(ByteBuffer.allocate(100));
+            cancelAndCheck(result);
             ch.close();
         }
     }
--- a/test/java/nio/channels/AsynchronousFileChannel/Basic.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/test/java/nio/channels/AsynchronousFileChannel/Basic.java	Sun Aug 23 12:53:45 2009 +0100
@@ -22,7 +22,7 @@
  */
 
 /* @test
- * @bug 4607272 6822643 6830721
+ * @bug 4607272 6822643 6830721 6842687
  * @summary Unit test for AsynchronousFileChannel
  */
 
@@ -195,8 +195,6 @@
                     }
                     public void failed(Throwable exc, Void att) {
                     }
-                    public void cancelled(Void att) {
-                    }
                 });
                 throw new RuntimeException("OverlappingFileLockException expected");
             } catch (OverlappingFileLockException x) {
@@ -229,8 +227,6 @@
             }
             public void failed(Throwable exc, Void att) {
             }
-            public void cancelled(Void att) {
-            }
         });
 
         // wait for handler to complete
@@ -318,8 +314,6 @@
                         }
                         public void failed(Throwable exc, Void att) {
                         }
-                        public void cancelled(Void att) {
-                        }
                     });
                     await(latch);
 
@@ -338,8 +332,41 @@
                 }
             } finally {
                 ch.close();
+                executor.shutdown();
             }
         }
+
+
+        // test sharing a thread pool between many channels
+        ExecutorService executor = Executors
+            .newFixedThreadPool(1+rand.nextInt(10), threadFactory);
+        final int n = 50 + rand.nextInt(50);
+        AsynchronousFileChannel[] channels = new AsynchronousFileChannel[n];
+        try {
+            for (int i=0; i<n; i++) {
+                Set<StandardOpenOption> opts = EnumSet.of(WRITE);
+                channels[i] = AsynchronousFileChannel.open(file, opts, executor);
+                final CountDownLatch latch = new CountDownLatch(1);
+                channels[i].write(genBuffer(), 0L, (Void)null, new CompletionHandler<Integer,Void>() {
+                    public void completed(Integer result, Void att) {
+                        latch.countDown();
+                    }
+                    public void failed(Throwable exc, Void att) {
+                    }
+                });
+                await(latch);
+
+                // close ~half the channels
+                if (rand.nextBoolean())
+                    channels[i].close();
+            }
+        } finally {
+            // close remaining channels
+            for (int i=0; i<n; i++) {
+                if (channels[i] != null) channels[i].close();
+            }
+            executor.shutdown();
+        }
     }
 
     // exercise asynchronous close
@@ -409,17 +436,7 @@
                 .open(file, WRITE, SYNC);
 
             // start write operation
-            final CountDownLatch latch = new CountDownLatch(1);
-            Future<Integer> res = ch.write(genBuffer(), 0L, (Void)null,
-                new CompletionHandler<Integer,Void>() {
-                    public void completed(Integer result, Void att) {
-                    }
-                    public void failed(Throwable exc, Void att) {
-                    }
-                    public void cancelled(Void att) {
-                        latch.countDown();
-                    }
-            });
+            Future<Integer> res = ch.write(genBuffer(), 0L);
 
             // cancel operation
             boolean cancelled = res.cancel(mayInterruptIfRunning);
@@ -456,10 +473,6 @@
                 throw new RuntimeException(x);
             }
 
-            // check that cancelled method is invoked
-            if (cancelled)
-                await(latch);
-
             ch.close();
         }
     }
@@ -547,8 +560,6 @@
             }
             public void failed(Throwable exc, Long position) {
             }
-            public void cancelled(Long position) {
-            }
         });
 
         // wait for writes to complete
@@ -574,8 +585,6 @@
             }
             public void failed(Throwable exc, Long position) {
             }
-            public void cancelled(Long position) {
-            }
         });
 
         // wait for reads to complete
--- a/test/java/nio/channels/AsynchronousFileChannel/CustomThreadPool.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/test/java/nio/channels/AsynchronousFileChannel/CustomThreadPool.java	Sun Aug 23 12:53:45 2009 +0100
@@ -22,7 +22,7 @@
  */
 
 /* @test
- * @bug 4607272
+ * @bug 4607272 6842687
  * @summary Unit test for java.nio.channels.AsynchronousFileChannel
  * @build CustomThreadPool MyThreadFactory
  * @run main/othervm -Djava.nio.channels.DefaultThreadPool.threadFactory=MyThreadFactory CustomThreadPool
@@ -51,8 +51,6 @@
                 }
                 public void failed(Throwable exc, AtomicReference<Thread> invoker) {
                 }
-                public void cancelled(AtomicReference<Thread> invoker) {
-                }
             });
         Thread t;
         while ((t = invoker.get()) == null) {
--- a/test/java/nio/channels/AsynchronousFileChannel/Lock.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/test/java/nio/channels/AsynchronousFileChannel/Lock.java	Sun Aug 23 12:53:45 2009 +0100
@@ -23,7 +23,7 @@
 
 
 /* @test
- * @bug 4607272 6814948
+ * @bug 4607272 6814948 6842687
  * @summary Unit test for AsynchronousFileChannel#lock method
  */
 
@@ -97,7 +97,7 @@
         slave.lock(0, 10, false);
 
         // this VM acquires lock on non-overlapping range
-        fl = ch.lock(10, 10, false, null, null).get();
+        fl = ch.lock(10, 10, false).get();
         fl.release();
 
         // done
--- a/test/java/nio/channels/AsynchronousServerSocketChannel/Basic.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/test/java/nio/channels/AsynchronousServerSocketChannel/Basic.java	Sun Aug 23 12:53:45 2009 +0100
@@ -22,7 +22,7 @@
  */
 
 /* @test
- * @bug 4607272
+ * @bug 4607272 6842687
  * @summary Unit test for AsynchronousServerSocketChannel
  * @run main/timeout=180 Basic
  */
@@ -104,8 +104,6 @@
             public void failed(Throwable exc, Void att) {
                 exception.set(exc);
             }
-            public void cancelled(Void att) {
-            }
         });
 
         // check AcceptPendingException
--- a/test/java/nio/channels/AsynchronousSocketChannel/Basic.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/test/java/nio/channels/AsynchronousSocketChannel/Basic.java	Sun Aug 23 12:53:45 2009 +0100
@@ -22,7 +22,7 @@
  */
 
 /* @test
- * @bug 4607272
+ * @bug 4607272 6842687
  * @summary Unit test for AsynchronousSocketChannel
  * @run main/timeout=600 Basic
  */
@@ -187,8 +187,6 @@
             public void failed(Throwable exc, Void att) {
                 connectException.set(exc);
             }
-            public void cancelled(Void att) {
-            }
         });
         while (connectException.get() == null) {
             Thread.sleep(100);
@@ -289,8 +287,6 @@
             public void failed(Throwable x, AsynchronousSocketChannel ch) {
                 writeException.set(x);
             }
-            public void cancelled(AsynchronousSocketChannel ch) {
-            }
         });
 
         // give time for socket buffer to fill up.
@@ -330,18 +326,8 @@
             SocketChannel peer = server.accept();
 
             // start read operation
-            final CountDownLatch latch = new CountDownLatch(1);
             ByteBuffer buf = ByteBuffer.allocate(1);
-            Future<Integer> res = ch.read(buf, (Void)null,
-                new CompletionHandler<Integer,Void>() {
-                    public void completed(Integer result, Void att) {
-                    }
-                    public void failed(Throwable exc, Void att) {
-                    }
-                    public void cancelled(Void att) {
-                        latch.countDown();
-                    }
-            });
+            Future<Integer> res = ch.read(buf);
 
             // cancel operation
             boolean cancelled = res.cancel(mayInterruptIfRunning);
@@ -362,8 +348,11 @@
             } catch (CancellationException x) {
             }
 
-            // check that completion handler executed.
-            latch.await();
+            // check that the cancel doesn't impact writing to the channel
+            if (!mayInterruptIfRunning) {
+                buf = ByteBuffer.wrap("a".getBytes());
+                ch.write(buf).get();
+            }
 
             ch.close();
             peer.close();
@@ -408,8 +397,6 @@
             }
             public void failed(Throwable exc, Void att) {
             }
-            public void cancelled(Void att) {
-            }
         });
 
         latch.await();
@@ -460,8 +447,6 @@
             }
             public void failed(Throwable exc, Void att) {
             }
-            public void cancelled(Void att) {
-            }
         });
 
         // trickle the writing
@@ -507,26 +492,24 @@
         }
 
         // scattering read that completes ascynhronously
-        final CountDownLatch latch = new CountDownLatch(1);
+        final CountDownLatch l1 = new CountDownLatch(1);
         ch.read(dsts, 0, dsts.length, 0L, TimeUnit.SECONDS, (Void)null,
             new CompletionHandler<Long,Void>() {
                 public void completed(Long result, Void att) {
                     long n = result;
                     if (n <= 0)
                         throw new RuntimeException("No bytes read");
-                    latch.countDown();
+                    l1.countDown();
                 }
                 public void failed(Throwable exc, Void att) {
                 }
-                public void cancelled(Void att) {
-                }
         });
 
         // write some bytes
         sc.write(genBuffer());
 
         // read should now complete
-        latch.await();
+        l1.await();
 
         // write more bytes
         sc.write(genBuffer());
@@ -535,10 +518,20 @@
         for (int i=0; i<dsts.length; i++) {
             dsts[i].rewind();
         }
-        long n = ch
-            .read(dsts, 0, dsts.length, 0L, TimeUnit.SECONDS, (Void)null, null).get();
-        if (n <= 0)
-            throw new RuntimeException("No bytes read");
+
+        final CountDownLatch l2 = new CountDownLatch(1);
+        ch.read(dsts, 0, dsts.length, 0L, TimeUnit.SECONDS, (Void)null,
+            new CompletionHandler<Long,Void>() {
+                public void completed(Long result, Void att) {
+                    long n = result;
+                    if (n <= 0)
+                        throw new RuntimeException("No bytes read");
+                    l2.countDown();
+                }
+                public void failed(Throwable exc, Void att) {
+                }
+        });
+        l2.await();
 
         ch.close();
         sc.close();
@@ -574,8 +567,6 @@
             }
             public void failed(Throwable exc, Void att) {
             }
-            public void cancelled(Void att) {
-            }
         });
 
         // read to EOF or buffer full
@@ -613,19 +604,29 @@
         ch.connect(server.address()).get();
         SocketChannel sc = server.accept();
 
+        // number of bytes written
+        final AtomicLong bytesWritten = new AtomicLong(0);
+
         // write buffers (should complete immediately)
         ByteBuffer[] srcs = genBuffers(1);
-        long n = ch
-            .write(srcs, 0, srcs.length, 0L, TimeUnit.SECONDS, (Void)null, null).get();
-        if (n <= 0)
-            throw new RuntimeException("No bytes written");
+        final CountDownLatch l1 = new CountDownLatch(1);
+        ch.write(srcs, 0, srcs.length, 0L, TimeUnit.SECONDS, (Void)null,
+            new CompletionHandler<Long,Void>() {
+                public void completed(Long result, Void att) {
+                    long n = result;
+                    if (n <= 0)
+                        throw new RuntimeException("No bytes read");
+                    bytesWritten.addAndGet(n);
+                    l1.countDown();
+                }
+                public void failed(Throwable exc, Void att) {
+                }
+        });
+        l1.await();
 
         // set to true to signal that no more buffers should be written
         final AtomicBoolean continueWriting = new AtomicBoolean(true);
 
-        // number of bytes written
-        final AtomicLong bytesWritten = new AtomicLong(n);
-
         // write until socket buffer is full so as to create the conditions
         // for when a write does not complete immediately
         srcs = genBuffers(1);
@@ -644,8 +645,6 @@
                 }
                 public void failed(Throwable exc, Void att) {
                 }
-                public void cancelled(Void att) {
-                }
         });
 
         // give time for socket buffer to fill up.
@@ -658,7 +657,7 @@
         ByteBuffer buf = ByteBuffer.allocateDirect(4096);
         long total = 0L;
         do {
-            n = sc.read(buf);
+            int n = sc.read(buf);
             if (n <= 0)
                 throw new RuntimeException("No bytes read");
             buf.rewind();
@@ -714,15 +713,27 @@
 
         System.out.println("-- timeout when reading --");
 
+        ByteBuffer dst = ByteBuffer.allocate(512);
+
+        final AtomicReference<Throwable> readException = new AtomicReference<Throwable>();
+
         // this read should timeout
-        ByteBuffer dst = ByteBuffer.allocate(512);
-        try {
-            ch.read(dst, 3, TimeUnit.SECONDS, (Void)null, null).get();
-            throw new RuntimeException("Read did not timeout");
-        } catch (ExecutionException x) {
-            if (!(x.getCause() instanceof InterruptedByTimeoutException))
-                throw new RuntimeException("InterruptedByTimeoutException expected");
+        ch.read(dst, 3, TimeUnit.SECONDS, (Void)null,
+            new CompletionHandler<Integer,Void>()
+        {
+            public void completed(Integer result, Void att) {
+                throw new RuntimeException("Should not complete");
+            }
+            public void failed(Throwable exc, Void att) {
+                readException.set(exc);
+            }
+        });
+        // wait for exception
+        while (readException.get() == null) {
+            Thread.sleep(100);
         }
+        if (!(readException.get() instanceof InterruptedByTimeoutException))
+            throw new RuntimeException("InterruptedByTimeoutException expected");
 
         // after a timeout then further reading should throw unspecified runtime exception
         boolean exceptionThrown = false;
@@ -752,8 +763,6 @@
             public void failed(Throwable exc, AsynchronousSocketChannel ch) {
                 writeException.set(exc);
             }
-            public void cancelled(AsynchronousSocketChannel ch) {
-            }
         });
 
         // wait for exception
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/java/nio/channels/AsynchronousSocketChannel/DieBeforeComplete.java	Sun Aug 23 12:53:45 2009 +0100
@@ -0,0 +1,136 @@
+/*
+ * Copyright 2008-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/* @test
+ * @bug 6842687
+ * @summary Unit test for AsynchronousSocketChannel/AsynchronousServerSocketChannel
+ */
+import java.nio.ByteBuffer;
+import java.nio.channels.*;
+import java.net.*;
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * Initiates I/O operation on a thread that terminates before the I/O completes.
+ */
+
+public class DieBeforeComplete {
+
+    public static void main(String[] args) throws Exception {
+        final AsynchronousServerSocketChannel listener =
+                AsynchronousServerSocketChannel.open().bind(new InetSocketAddress(0));
+
+        InetAddress lh = InetAddress.getLocalHost();
+        int port = ((InetSocketAddress) (listener.getLocalAddress())).getPort();
+        final SocketAddress sa = new InetSocketAddress(lh, port);
+
+        // -- accept --
+
+        // initiate accept in a thread that dies before connection is established
+        Future<AsynchronousSocketChannel> r1 =
+                initiateAndDie(new Task<AsynchronousSocketChannel>() {
+            public Future<AsynchronousSocketChannel> run() {
+                return listener.accept();
+            }});
+
+        // establish and accept connection
+        SocketChannel peer = SocketChannel.open(sa);
+        final AsynchronousSocketChannel channel = r1.get();
+
+        // --- read --
+
+        // initiate read in a thread that dies befores bytes are available
+        final ByteBuffer dst = ByteBuffer.allocate(100);
+        Future<Integer> r2 = initiateAndDie(new Task<Integer>() {
+            public Future<Integer> run() {
+                return channel.read(dst);
+            }});
+
+        // send bytes
+        peer.write(ByteBuffer.wrap("hello".getBytes()));
+        int nread = r2.get();
+        if (nread <= 0)
+            throw new RuntimeException("Should have read at least one byte");
+
+        // -- write --
+
+        // initiate writes in threads that dies
+        boolean completedImmediately;
+        Future<Integer> r3;
+        do {
+            final ByteBuffer src = ByteBuffer.wrap(new byte[10000]);
+            r3 = initiateAndDie(new Task<Integer>() {
+                public Future<Integer> run() {
+                    return channel.write(src);
+                }});
+            try {
+                int nsent = r3.get(5, TimeUnit.SECONDS);
+                if (nsent <= 0)
+                    throw new RuntimeException("Should have wrote at least one byte");
+                completedImmediately = true;
+            } catch (TimeoutException x) {
+                completedImmediately = false;
+            }
+        } while (completedImmediately);
+
+        // drain connection
+        peer.configureBlocking(false);
+        ByteBuffer src = ByteBuffer.allocateDirect(10000);
+        do {
+            src.clear();
+            nread = peer.read(src);
+            if (nread == 0) {
+                Thread.sleep(100);
+                nread = peer.read(src);
+            }
+        } while (nread > 0);
+
+        // write should complete now
+        int nsent = r3.get();
+        if (nsent <= 0)
+            throw new RuntimeException("Should have wrote at least one byte");
+    }
+
+    static interface Task<T> {
+        Future<T> run();
+    }
+
+    static <T> Future<T> initiateAndDie(final Task<T> task) {
+        final AtomicReference<Future<T>> result = new AtomicReference<Future<T>>();
+        Runnable r = new Runnable() {
+            public void run() {
+                result.set(task.run());
+            }
+        };
+        Thread t = new Thread(r);
+        t.start();
+        while (t.isAlive()) {
+            try {
+                t.join();
+            } catch (InterruptedException x) {
+            }
+        }
+        return result.get();
+    }
+}
--- a/test/java/nio/channels/AsynchronousSocketChannel/StressLoopback.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/test/java/nio/channels/AsynchronousSocketChannel/StressLoopback.java	Sun Aug 23 12:53:45 2009 +0100
@@ -22,7 +22,7 @@
  */
 
 /* @test
- * @bug 6834246
+ * @bug 6834246 6842687
  * @summary Stress test connections through the loopback interface
  */
 
@@ -114,8 +114,6 @@
                     exc.printStackTrace();
                     closeUnchecked(channel);
                 }
-                public void cancelled(Void att) {
-                }
             });
         }
 
@@ -156,8 +154,6 @@
                     exc.printStackTrace();
                     closeUnchecked(channel);
                 }
-                public void cancelled(Void att) {
-                }
             });
         }
 
--- a/test/java/nio/channels/FileChannel/ReleaseOnCloseDeadlock.java	Sat Aug 22 17:40:18 2009 +0100
+++ b/test/java/nio/channels/FileChannel/ReleaseOnCloseDeadlock.java	Sun Aug 23 12:53:45 2009 +0100
@@ -22,7 +22,7 @@
  */
 
 /* @test
- * @bug 6543863
+ * @bug 6543863 6842687
  * @summary Try to cause a deadlock between (Asynchronous)FileChannel.close
  *   and FileLock.release
  */
@@ -56,7 +56,7 @@
         AsynchronousFileChannel ch = AsynchronousFileChannel.open(file, READ, WRITE);
         for (int i=0; i<LOCK_COUNT; i++) {
             try {
-                locks[i] = ch.lock(i, 1, true, null, null).get();
+                locks[i] = ch.lock(i, 1, true).get();
             } catch (InterruptedException x) {
                 throw new RuntimeException(x);
             } catch (ExecutionException x) {