FULL PRODUCT VERSION :
java version "1.8.0_31"
Java(TM) SE Runtime Environment (build 1.8.0_31-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.31-b07, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
OS X 10.10.2 (14C109)

EXTRA RELEVANT SYSTEM CONFIGURATION :
Filesystem: "Journaled HFS+" or "jhfs+" - Mac OS Extended (Journaled)

A DESCRIPTION OF THE PROBLEM :
A directory is watched recursively using java.nio.file.WatchService and the code provided at "http://docs.oracle.com/javase/tutorial/essential/io/examples/WatchDir.java". If a hierarchy of directories is repeatedly renamed a top levels a deadlock can be observed.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1) Run the WatchDir example at "http://docs.oracle.com/javase/tutorial/essential/io/examples/WatchDir.java" with recursion enabled to any directory.

2) Copy the provided python script (see bottom of this textfield) in the initially watched directory and execute it from there. It creates a folder hierarchy with a depth of 100 subfolders and alternatively renames directories at level 0 and level 1.

3) After several iterations a deadlock occurs at "sun.nio.fs.PollingWatchService$PollingWatchKey.cancel(PollingWatchService.java:308)" and "sun.nio.fs.PollingWatchService$PollingWatchKey.disable(PollingWatchService.java:299)". Further information can be found in the provided thread dump.

PYTHON SCRIPT:

import os
import shutil
import time

def toPath( pathElements ):
    "convert path elements to path string"
    
    path = "";
    for element in pathElements:
        path += element + "/"
    return path

def cleanCurrentDir():
    "remove every dir"
    for content in os.listdir(os.getcwd()):
        if( os.path.isdir(content) ):
            shutil.rmtree(content)

# clean up
cleanCurrentDir()

# define depth of hierachie
depth = 100;
dirPrefix = "dir_"

# construct list of path elements
pathElements=[]
for i in range(depth):
    pathElements.append("dir")

#rename first to path elements
pathElements[0] = dirPrefix + "0";
pathElements[1] = dirPrefix + "0";

# convert to path
entirePath = toPath(pathElements)

# create hierachie
os.makedirs(entirePath)

NIterations = 1000
sleepTime = 1.5 # in seconds

for i in range(NIterations):
    
    # rename dirs
    newName = dirPrefix + str(i+1);
    if( i % 2 == 0):
        
        #raw_input("Name of directory changing at level 0. Press enter to continue...")
        
        os.rename(pathElements[0], newName)
        pathElements[0] = newName
        
        # simulate delay
        time.sleep(sleepTime)

    else:
        #raw_input("Name of directory changing at level 1. Press enter to continue...")
        
        os.chdir(pathElements[0])
        os.rename(pathElements[1], newName)
        pathElements[1] = newName
        os.chdir("..")
        
        # simulate delay
        time.sleep(2*sleepTime)
        
    print "current paths " + toPath(pathElements[:3]) + "..."



EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Expected results would be watched directories without deadlock.
ACTUAL -
The actual result is a deadlock, which leads to non watched directories.

ERROR MESSAGES/STACK TRACES THAT OCCUR :

2015-03-03 14:20:01
Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.31-b07 mixed mode):

"RMI TCP Connection(2)-192.168.123.180" #16 daemon prio=9 os_prio=31 tid=0x00007fa0d4814800 nid=0x5c03 runnable [0x000000011ee4a000]
   java.lang.Thread.State: RUNNABLE
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream.java:150)
at java.net.SocketInputStream.read(SocketInputStream.java:121)
at java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
at java.io.BufferedInputStream.read(BufferedInputStream.java:265)
- locked <0x0000000795fead68> (a java.io.BufferedInputStream)
at java.io.FilterInputStream.read(FilterInputStream.java:83)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:550)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:826)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$240(TCPTransport.java:683)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler$$Lambda$1/398973873.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:682)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

   Locked ownable synchronizers:
- <0x0000000795c05f18> (a java.util.concurrent.ThreadPoolExecutor$Worker)

"JMX server connection timeout 15" #15 daemon prio=9 os_prio=31 tid=0x00007fa0d40d2800 nid=0x5a03 in Object.wait() [0x000000011ec73000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
at com.sun.jmx.remote.internal.ServerCommunicatorAdmin$Timeout.run(ServerCommunicatorAdmin.java:168)
- locked <0x0000000795d9da50> (a [I)
at java.lang.Thread.run(Thread.java:745)

   Locked ownable synchronizers:
- None

"RMI Scheduler(0)" #14 daemon prio=9 os_prio=31 tid=0x00007fa0d399a800 nid=0x5803 waiting on condition [0x000000011eb70000]
   java.lang.Thread.State: TIMED_WAITING (parking)
at sun.misc.Unsafe.park(Native Method)
- parking to wait for <0x0000000795b5add8> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093)
at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1067)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

   Locked ownable synchronizers:
- None

"RMI TCP Connection(1)-192.168.123.180" #13 daemon prio=9 os_prio=31 tid=0x00007fa0d40b0800 nid=0x5603 runnable [0x000000011ea6c000]
   java.lang.Thread.State: RUNNABLE
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream.java:150)
at java.net.SocketInputStream.read(SocketInputStream.java:121)
at java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
at java.io.BufferedInputStream.read(BufferedInputStream.java:265)
- locked <0x0000000795d6ff50> (a java.io.BufferedInputStream)
at java.io.FilterInputStream.read(FilterInputStream.java:83)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:550)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:826)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$240(TCPTransport.java:683)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler$$Lambda$1/398973873.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:682)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

   Locked ownable synchronizers:
- <0x0000000795c05058> (a java.util.concurrent.ThreadPoolExecutor$Worker)

"RMI TCP Accept-0" #12 daemon prio=9 os_prio=31 tid=0x00007fa0d40a7800 nid=0x5507 runnable [0x000000011e96a000]
   java.lang.Thread.State: RUNNABLE
at java.net.PlainSocketImpl.socketAccept(Native Method)
at java.net.AbstractPlainSocketImpl.accept(AbstractPlainSocketImpl.java:404)
at java.net.ServerSocket.implAccept(ServerSocket.java:545)
at java.net.ServerSocket.accept(ServerSocket.java:513)
at sun.management.jmxremote.LocalRMIServerSocketFactory$1.accept(LocalRMIServerSocketFactory.java:52)
at sun.rmi.transport.tcp.TCPTransport$AcceptLoop.executeAcceptLoop(TCPTransport.java:400)
at sun.rmi.transport.tcp.TCPTransport$AcceptLoop.run(TCPTransport.java:372)
at java.lang.Thread.run(Thread.java:745)

   Locked ownable synchronizers:
- None

"Attach Listener" #10 daemon prio=9 os_prio=31 tid=0x00007fa0d483b000 nid=0x4d03 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
- None

"Thread-0" #9 daemon prio=5 os_prio=31 tid=0x00007fa0d4059800 nid=0x4b03 waiting for monitor entry [0x000000011e753000]
   java.lang.Thread.State: BLOCKED (on object monitor)
at sun.nio.fs.PollingWatchService$PollingWatchKey.cancel(PollingWatchService.java:308)
- waiting to lock <0x00000007957c0a80> (a java.util.HashMap)
at sun.nio.fs.PollingWatchService$PollingWatchKey.poll(PollingWatchService.java:331)
- locked <0x00000007958970f0> (a sun.nio.fs.PollingWatchService$PollingWatchKey)
at sun.nio.fs.PollingWatchService$PollingWatchKey$1.run(PollingWatchService.java:290)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

   Locked ownable synchronizers:
- <0x000000079582bf38> (a java.util.concurrent.ThreadPoolExecutor$Worker)

"Service Thread" #8 daemon prio=9 os_prio=31 tid=0x00007fa0d4044000 nid=0x4703 runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
- None

"C1 CompilerThread2" #7 daemon prio=9 os_prio=31 tid=0x00007fa0d383f000 nid=0x4503 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
- None

"C2 CompilerThread1" #6 daemon prio=9 os_prio=31 tid=0x00007fa0d383c800 nid=0x4303 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
- None

"C2 CompilerThread0" #5 daemon prio=9 os_prio=31 tid=0x00007fa0d5017000 nid=0x4103 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
- None

"Signal Dispatcher" #4 daemon prio=9 os_prio=31 tid=0x00007fa0d5000000 nid=0x3013 runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
- None

"Finalizer" #3 daemon prio=8 os_prio=31 tid=0x00007fa0d4027000 nid=0x2d03 in Object.wait() [0x000000011c721000]
   java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on <0x00000007955862f8> (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:142)
- locked <0x00000007955862f8> (a java.lang.ref.ReferenceQueue$Lock)
at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:158)
at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:209)

   Locked ownable synchronizers:
- None

"Reference Handler" #2 daemon prio=10 os_prio=31 tid=0x00007fa0d4808800 nid=0x2b03 in Object.wait() [0x000000011c61e000]
   java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
- waiting on <0x0000000795585d68> (a java.lang.ref.Reference$Lock)
at java.lang.Object.wait(Object.java:502)
at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:157)
- locked <0x0000000795585d68> (a java.lang.ref.Reference$Lock)

   Locked ownable synchronizers:
- None

"main" #1 prio=5 os_prio=31 tid=0x00007fa0d4008000 nid=0x1303 waiting for monitor entry [0x0000000104f26000]
   java.lang.Thread.State: BLOCKED (on object monitor)
at sun.nio.fs.PollingWatchService$PollingWatchKey.disable(PollingWatchService.java:299)
- waiting to lock <0x00000007958970f0> (a sun.nio.fs.PollingWatchService$PollingWatchKey)
at sun.nio.fs.PollingWatchService.doPrivilegedRegister(PollingWatchService.java:171)
- locked <0x00000007957c0a80> (a java.util.HashMap)
- locked <0x00000007957c0a70> (a java.lang.Object)
at sun.nio.fs.PollingWatchService.access$000(PollingWatchService.java:45)
at sun.nio.fs.PollingWatchService$2.run(PollingWatchService.java:130)
at sun.nio.fs.PollingWatchService$2.run(PollingWatchService.java:127)
at java.security.AccessController.doPrivileged(Native Method)
at sun.nio.fs.PollingWatchService.register(PollingWatchService.java:126)
at sun.nio.fs.UnixPath.register(UnixPath.java:897)
at sun.nio.fs.AbstractPath.register(AbstractPath.java:104)
at com.watchdir.test.WatchDir.register(WatchDir.java:61)
at com.watchdir.test.WatchDir.access$0(WatchDir.java:60)
at com.watchdir.test.WatchDir$1.preVisitDirectory(WatchDir.java:86)
at com.watchdir.test.WatchDir$1.preVisitDirectory(WatchDir.java:1)
at java.nio.file.Files.walkFileTree(Files.java:2677)
at java.nio.file.Files.walkFileTree(Files.java:2742)
at com.watchdir.test.WatchDir.registerAll(WatchDir.java:81)
at com.watchdir.test.WatchDir.processEvents(WatchDir.java:153)
at com.watchdir.test.WatchDir.main(WatchDir.java:194)

   Locked ownable synchronizers:
- None

"VM Thread" os_prio=31 tid=0x00007fa0d4801000 nid=0x2903 runnable

"GC task thread#0 (ParallelGC)" os_prio=31 tid=0x00007fa0d380f800 nid=0x2103 runnable

"GC task thread#1 (ParallelGC)" os_prio=31 tid=0x00007fa0d3810000 nid=0x2303 runnable

"GC task thread#2 (ParallelGC)" os_prio=31 tid=0x00007fa0d3810800 nid=0x2503 runnable

"GC task thread#3 (ParallelGC)" os_prio=31 tid=0x00007fa0d3811800 nid=0x2703 runnable

"VM Periodic Task Thread" os_prio=31 tid=0x00007fa0d402a800 nid=0x4903 waiting on condition

JNI global references: 289


Found one Java-level deadlock:
=============================
"Thread-0":
  waiting to lock monitor 0x00007fa0d5010288 (object 0x00000007957c0a80, a java.util.HashMap),
  which is held by "main"
"main":
  waiting to lock monitor 0x00007fa0d500ef48 (object 0x00000007958970f0, a sun.nio.fs.PollingWatchService$PollingWatchKey),
  which is held by "Thread-0"

Java stack information for the threads listed above:
===================================================
"Thread-0":
at sun.nio.fs.PollingWatchService$PollingWatchKey.cancel(PollingWatchService.java:308)
- waiting to lock <0x00000007957c0a80> (a java.util.HashMap)
at sun.nio.fs.PollingWatchService$PollingWatchKey.poll(PollingWatchService.java:331)
- locked <0x00000007958970f0> (a sun.nio.fs.PollingWatchService$PollingWatchKey)
at sun.nio.fs.PollingWatchService$PollingWatchKey$1.run(PollingWatchService.java:290)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
"main":
at sun.nio.fs.PollingWatchService$PollingWatchKey.disable(PollingWatchService.java:299)
- waiting to lock <0x00000007958970f0> (a sun.nio.fs.PollingWatchService$PollingWatchKey)
at sun.nio.fs.PollingWatchService.doPrivilegedRegister(PollingWatchService.java:171)
- locked <0x00000007957c0a80> (a java.util.HashMap)
- locked <0x00000007957c0a70> (a java.lang.Object)
at sun.nio.fs.PollingWatchService.access$000(PollingWatchService.java:45)
at sun.nio.fs.PollingWatchService$2.run(PollingWatchService.java:130)
at sun.nio.fs.PollingWatchService$2.run(PollingWatchService.java:127)
at java.security.AccessController.doPrivileged(Native Method)
at sun.nio.fs.PollingWatchService.register(PollingWatchService.java:126)
at sun.nio.fs.UnixPath.register(UnixPath.java:897)
at sun.nio.fs.AbstractPath.register(AbstractPath.java:104)
at com.watchdir.test.WatchDir.register(WatchDir.java:61)
at com.watchdir.test.WatchDir.access$0(WatchDir.java:60)
at com.watchdir.test.WatchDir$1.preVisitDirectory(WatchDir.java:86)
at com.watchdir.test.WatchDir$1.preVisitDirectory(WatchDir.java:1)
at java.nio.file.Files.walkFileTree(Files.java:2677)
at java.nio.file.Files.walkFileTree(Files.java:2742)
at com.watchdir.test.WatchDir.registerAll(WatchDir.java:81)
at com.watchdir.test.WatchDir.processEvents(WatchDir.java:153)
at com.watchdir.test.WatchDir.main(WatchDir.java:194)

Found 1 deadlock.


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
This source code can also be found at "http://docs.oracle.com/javase/tutorial/essential/io/examples/WatchDir.java".

/*
 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. 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 Oracle 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.StandardWatchEventKinds.*;
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) {
            Path 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, BasicFileAttributes attrs)
                throws IOException
            {
                register(dir);
                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 (Files.isDirectory(child, NOFOLLOW_LINKS)) {
                            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();
    }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
No workaround found yet.