diff -r 115e09b7a004 -r 3acf8e5e2ca0 jdk/src/share/sample/nio/file/WatchDir.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/sample/nio/file/WatchDir.java	Sun Feb 15 12:25:54 2009 +0000
@@ -0,0 +1,196 @@
+/*
+ * Copyright 2008-2009 Sun Microsystems, Inc.  All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   - Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   - Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *
+ *   - Neither the name of Sun Microsystems nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+import java.nio.file.*;
+import static java.nio.file.StandardWatchEventKind.*;
+import static java.nio.file.LinkOption.*;
+import java.nio.file.attribute.*;
+import java.io.*;
+import java.util.*;
+
+/**
+ * Example to watch a directory (or tree) for changes to files.
+ */
+
+public class WatchDir {
+
+    private final WatchService watcher;
+    private final Map<WatchKey,Path> keys;
+    private final boolean recursive;
+    private boolean trace = false;
+
+    @SuppressWarnings("unchecked")
+    static <T> WatchEvent<T> cast(WatchEvent<?> event) {
+        return (WatchEvent<T>)event;
+    }
+
+    /**
+     * Register the given directory with the WatchService
+     */
+    private void register(Path dir) throws IOException {
+        WatchKey key = dir.register(watcher, ENTRY_CREATE, ENTRY_DELETE, ENTRY_MODIFY);
+        if (trace) {
+            FileRef prev = keys.get(key);
+            if (prev == null) {
+                System.out.format("register: %s\n", dir);
+            } else {
+                if (!dir.equals(prev)) {
+                    System.out.format("update: %s -> %s\n", prev, dir);
+                }
+            }
+        }
+        keys.put(key, dir);
+    }
+
+    /**
+     * Register the given directory, and all its sub-directories, with the
+     * WatchService.
+     */
+    private void registerAll(final Path start) throws IOException {
+        // register directory and sub-directories
+        Files.walkFileTree(start, new SimpleFileVisitor<Path>() {
+            @Override
+            public FileVisitResult preVisitDirectory(Path dir) {
+                try {
+                    register(dir);
+                } catch (IOException x) {
+                    throw new IOError(x);
+                }
+                return FileVisitResult.CONTINUE;
+            }
+        });
+    }
+
+    /**
+     * Creates a WatchService and registers the given directory
+     */
+    WatchDir(Path dir, boolean recursive) throws IOException {
+        this.watcher = FileSystems.getDefault().newWatchService();
+        this.keys = new HashMap<WatchKey,Path>();
+        this.recursive = recursive;
+
+        if (recursive) {
+            System.out.format("Scanning %s ...\n", dir);
+            registerAll(dir);
+            System.out.println("Done.");
+        } else {
+            register(dir);
+        }
+
+        // enable trace after initial registration
+        this.trace = true;
+    }
+
+    /**
+     * Process all events for keys queued to the watcher
+     */
+    void processEvents() {
+        for (;;) {
+
+            // wait for key to be signalled
+            WatchKey key;
+            try {
+                key = watcher.take();
+            } catch (InterruptedException x) {
+                return;
+            }
+
+            Path dir = keys.get(key);
+            if (dir == null) {
+                System.err.println("WatchKey not recognized!!");
+                continue;
+            }
+
+            for (WatchEvent<?> event: key.pollEvents()) {
+                WatchEvent.Kind kind = event.kind();
+
+                // TBD - provide example of how OVERFLOW event is handled
+                if (kind == OVERFLOW) {
+                    continue;
+                }
+
+                // Context for directory entry event is the file name of entry
+                WatchEvent<Path> ev = cast(event);
+                Path name = ev.context();
+                Path child = dir.resolve(name);
+
+                // print out event
+                System.out.format("%s: %s\n", event.kind().name(), child);
+
+                // if directory is created, and watching recursively, then
+                // register it and its sub-directories
+                if (recursive && (kind == ENTRY_CREATE)) {
+                    try {
+                        if (Attributes.readBasicFileAttributes(child, NOFOLLOW_LINKS).isDirectory()) {
+                            registerAll(child);
+                        }
+                    } catch (IOException x) {
+                        // ignore to keep sample readbale
+                    }
+                }
+            }
+
+            // reset key and remove from set if directory no longer accessible
+            boolean valid = key.reset();
+            if (!valid) {
+                keys.remove(key);
+
+                // all directories are inaccessible
+                if (keys.isEmpty()) {
+                    break;
+                }
+            }
+        }
+    }
+
+    static void usage() {
+        System.err.println("usage: java WatchDir [-r] dir");
+        System.exit(-1);
+    }
+
+    public static void main(String[] args) throws IOException {
+        // parse arguments
+        if (args.length == 0 || args.length > 2)
+            usage();
+        boolean recursive = false;
+        int dirArg = 0;
+        if (args[0].equals("-r")) {
+            if (args.length < 2)
+                usage();
+            recursive = true;
+            dirArg++;
+        }
+
+        // register directory and process its events
+        Path dir = Paths.get(args[dirArg]);
+        new WatchDir(dir, recursive).processEvents();
+    }
+}