--- a/src/share/classes/java/nio/file/FileSystem.java	Tue Oct 14 09:40:04 2008 +0100
+++ b/src/share/classes/java/nio/file/FileSystem.java	Tue Oct 14 09:59:39 2008 +0100
@@ -180,12 +180,12 @@
      * may result in the creation of a new file hierarchy with its own
      * top-level directory.
      *
-     * <p> When a security manager is installed, and it denies an unspecified
-     * permission to access the root directory, then the root directory is
-     * not included in the list returned by this method. In the case of the
-     * default provider, the {@link SecurityManager#checkRead(String)} method is
-     * invoked to check read access to the root directory in each file store
-     * hierarchy.
+     * <p> When a security manager is installed, it is invoked to check access
+     * to the each root directory. If denied, the root directory is not returned
+     * by the iterator. In the case of the default provider, the {@link
+     * SecurityManager#checkRead(String)} method is invoked to check read access
+     * to each root directory. It is system dependent if the permission checks
+     * are done when the iterator is obtained or during iteration.
      *
      * @return  An object to iterate over the root directories
      */
@@ -198,13 +198,15 @@
      * FileStore FileStores} for this file system. The order of the elements is
      * not defined and the file stores may change during the lifetime of the
      * Java virtual machine. When an I/O error occurs, perhaps because a file
-     * store is not accessible, then it is not returned by the iterator. When a
-     * security manager is installed, and it denies access to a file store, then
-     * the file store is not included. In the case of the default provider, the
-     * {@link SecurityManager#checkRead(String)} method is invoked to check read
-     * access to the <em>top-most</em> directory of the file system. Whether that
-     * directory corresponds to the root directory of a distinct file hierarchy
-     * is implementation specific.
+     * store is not accessible, then it is not returned by the iterator.
+     *
+     * <p> When a security manager is installed, it is invoked to check access
+     * to each file store. If denied, the file store is not returned by the
+     * iterator. In the case of the default provider, the {@link
+     * SecurityManager#checkRead(String)} method is invoked to check read access
+     * to the file store's <em>top-most</em> directory. It is system dependent
+     * if the permission checks are done when the iterator is obtained or during
+     * iteration.
      *
      * <p> <b>Usage Example:</b>
      * Suppose we want to print the space usage for all file stores:

--- a/src/share/classes/java/nio/file/spi/FileSystemProvider.java	Tue Oct 14 09:40:04 2008 +0100
+++ b/src/share/classes/java/nio/file/spi/FileSystemProvider.java	Tue Oct 14 09:59:39 2008 +0100
@@ -140,20 +140,20 @@
     }
 
     /**
-     * Returns an object to iterate over the installed file system providers.
+     * Returns a list of the installed file system providers.
      *
      * <p> The first invocation of this method causes the default provider to be
      * initialized (if not already initialized) and loads any other installed
      * providers as described by the {@link FileSystems} class.
      *
-     * @return  An object to iterate over the installed file system providers. The
-     *          iterator returns at least one element, that is the default file
+     * @return  An unmodifiable list of the installed file system providers. The
+     *          list contains at least one element, that is the default file
      *          system provider
      *
      * @throws  ServiceConfigurationError
      *          When an error occurs while loading a service provider
      */
-    public static Iterable<FileSystemProvider> installedProviders() {
+    public static List<FileSystemProvider> installedProviders() {
         if (installedProviders == null) {
             // ensure default provider is initialized
             FileSystemProvider defaultProvider = FileSystems.getDefault().provider();

--- a/src/solaris/classes/sun/nio/fs/UnixFileSystem.java	Tue Oct 14 09:40:04 2008 +0100
+++ b/src/solaris/classes/sun/nio/fs/UnixFileSystem.java	Tue Oct 14 09:59:39 2008 +0100
@@ -131,16 +131,21 @@
      */
     @Override
     public final Iterable<Path> getRootDirectories() {
-        List<Path> roots;
-        try {
-            SecurityManager sm = System.getSecurityManager();
-            if (sm != null)
-                sm.checkRead(rootDirectory.toString());
-            roots = Collections.unmodifiableList(Arrays.asList((Path)rootDirectory));
-        } catch (SecurityException x) {
-            roots = Collections.emptyList();
-        }
-        return roots;
+        final List<Path> allowedList =
+           Collections.unmodifiableList(Arrays.asList((Path)rootDirectory));
+        return new Iterable<Path>() {
+            public Iterator<Path> iterator() {
+                try {
+                    SecurityManager sm = System.getSecurityManager();
+                    if (sm != null)
+                        sm.checkRead(rootDirectory.toString());
+                    return allowedList.iterator();
+                } catch (SecurityException x) {
+                    List<Path> disallowed = Collections.emptyList();
+                    return disallowed.iterator();
+                }
+            }
+        };
     }
 
     /**
@@ -167,9 +172,8 @@
         private final Iterator<UnixMountEntry> entries;
         private FileStore next;
 
-        FileStoreIterator(Iterator<UnixMountEntry> entries) {
-            this.entries = entries;
-            this.next = null;
+        FileStoreIterator() {
+            this.entries = getMountEntries().iterator();
         }
 
         private FileStore readNext() {
@@ -225,11 +229,9 @@
 
     @Override
     public final Iterable<FileStore> getFileStores() {
-        Iterator<UnixMountEntry> entries = getMountEntries().iterator();
-        final FileStoreIterator iterator = new FileStoreIterator(entries);
         return new Iterable<FileStore>() {
             public Iterator<FileStore> iterator() {
-                return iterator;
+                return new FileStoreIterator();
             }
         };
     }

--- a/src/windows/classes/sun/nio/fs/WindowsFileSystem.java	Tue Oct 14 09:40:04 2008 +0100
+++ b/src/windows/classes/sun/nio/fs/WindowsFileSystem.java	Tue Oct 14 09:59:39 2008 +0100
@@ -119,8 +119,8 @@
         throw new UnsupportedOperationException();
     }
 
-    @Override
-    public Iterable<Path> getRootDirectories() {
+    // return new iterator over root directories
+    private Iterator<Path> rootDirectoryIterator() {
         // FIXME - we should replace this with calls to FindFirstVolume and
         // FindNextVolume
         int drives = 0;
@@ -150,19 +150,27 @@
                 result.add(WindowsPath.createFromNormalizedPath(this, root));
             }
         }
-        return Collections.unmodifiableList(result);
+        return Collections.unmodifiableList(result).iterator();
+    }
+
+    @Override
+    public Iterable<Path> getRootDirectories() {
+        return new Iterable<Path>() {
+            public Iterator<Path> iterator() {
+                return rootDirectoryIterator();
+            }
+        };
     }
 
     /**
      * Iterator returned by getFileStores method.
      */
-    private static class FileStoreIterator implements Iterator<FileStore> {
+    private class FileStoreIterator implements Iterator<FileStore> {
         private final Iterator<Path> roots;
         private FileStore next;
 
-        FileStoreIterator(Iterator<Path> roots) {
-            this.roots = roots;
-            this.next = null;
+        FileStoreIterator() {
+            this.roots = getRootDirectories().iterator();
         }
 
         private FileStore readNext() {
@@ -216,11 +224,9 @@
 
     @Override
     public Iterable<FileStore> getFileStores() {
-        Iterator<Path> rootsIterator = getRootDirectories().iterator();
-        final FileStoreIterator iterator = new FileStoreIterator(rootsIterator);
         return new Iterable<FileStore>() {
             public Iterator<FileStore> iterator() {
-                return iterator;
+                return new FileStoreIterator();
             }
         };
     }