diff -r 5853628b0e63 -r df1302c8e4bd jdk/test/java/nio/file/WatchService/LotsOfCancels.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/nio/file/WatchService/LotsOfCancels.java	Fri Sep 05 12:18:31 2014 +0100
@@ -0,0 +1,119 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/* @test
+ * @bug 8029516
+ * @summary Bash on WatchKey.cancel with a view to causing a crash when
+ *    an outstanding I/O operation on directory completes after the
+ *    directory has been closed
+ */
+
+import java.nio.file.ClosedWatchServiceException;
+import java.nio.file.FileSystems;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.WatchKey;
+import java.nio.file.WatchService;
+import static java.nio.file.StandardWatchEventKinds.*;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+public class LotsOfCancels {
+
+    // set to true for any exceptions
+    static volatile boolean failed;
+
+    public static void main(String[] args) throws Exception {
+
+        // create a bunch of directories. Create two tasks for each directory,
+        // one to bash on cancel, the other to poll the events
+        ExecutorService pool = Executors.newCachedThreadPool();
+        try {
+            Path top = Files.createTempDirectory("work");
+            top.toFile().deleteOnExit();
+            for (int i=1; i<=16; i++) {
+                Path dir = Files.createDirectory(top.resolve("dir-" + i));
+                WatchService watcher = FileSystems.getDefault().newWatchService();
+                pool.submit(() -> handle(dir, watcher));
+                pool.submit(() -> poll(watcher));
+            }
+        } finally {
+            pool.shutdown();
+        }
+
+        // give thread pool lots of time to terminate
+        if (!pool.awaitTermination(5L, TimeUnit.MINUTES))
+            throw new RuntimeException("Thread pool did not terminate");
+
+        if (failed)
+            throw new RuntimeException("Test failed, see log for details");
+    }
+
+    /**
+     * Stress the given WatchService, specifically the cancel method, in
+     * the given directory. Closes the WatchService when done.
+     */
+    static void handle(Path dir, WatchService watcher) {
+        try {
+            try {
+                Path file = dir.resolve("anyfile");
+                for (int i=0; i<2000; i++) {
+                    WatchKey key = dir.register(watcher, ENTRY_CREATE, ENTRY_DELETE);
+                    Files.createFile(file);
+                    Files.delete(file);
+                    key.cancel();
+                }
+            } finally {
+                watcher.close();
+            }
+        } catch (Exception e) {
+            e.printStackTrace();
+            failed = true;
+        }
+    }
+
+    /**
+     * Polls the given WatchService in a tight loop. This keeps the event
+     * queue drained, it also hogs a CPU core which seems necessary to
+     * tickle the original bug.
+     */
+    static void poll(WatchService watcher) {
+        try {
+            for (;;) {
+                WatchKey key = watcher.take();
+                if (key != null) {
+                    key.pollEvents();
+                    key.reset();
+                }
+            }
+        } catch (ClosedWatchServiceException expected) {
+            // nothing to do
+        } catch (Exception e) {
+            e.printStackTrace();
+            failed = true;
+        }
+    }
+
+}
+