1 /*

     2  * Copyright 2008 Sun Microsystems, Inc.  All Rights Reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  */

    23 

    24 /*

    25  * @test

    26  * @bug 6717789

    27  * @summary Check that a lock is not held when a LeaseManager expires.

    28  * @author Eamonn McManus

    29  */

    30 

    31 import com.sun.jmx.event.LeaseManager;

    32 import java.lang.management.ManagementFactory;

    33 import java.lang.management.ThreadMXBean;

    34 import java.util.Arrays;

    35 import java.util.concurrent.Semaphore;

    36 import java.util.concurrent.TimeUnit;

    37 

    38 public class LeaseManagerDeadlockTest {

    39     public static String failure;

    40     public static LeaseManager leaseManager;

    41     public static Semaphore callbackThreadCompleted = new Semaphore(0);

    42     public static Object lock = new Object();

    43 

    44     public static Runnable triggerDeadlock = new Runnable() {

    45         public void run() {

    46             Runnable pingLeaseManager = new Runnable() {

    47                 public void run() {

    48                     System.out.println("Ping thread starts");

    49                     synchronized (lock) {

    50                         leaseManager.lease(1);

    51                     }

    52                     System.out.println("Ping thread completes");

    53                 }

    54             };

    55             Thread t = new Thread(pingLeaseManager);

    56             t.start();

    57             try {

    58                 Thread.sleep(10);  // enough time for ping thread to grab lock

    59                 synchronized (lock) {

    60                     t.join();

    61                 }

    62             } catch (InterruptedException e) {

    63                 fail(e.toString());

    64             }

    65             System.out.println("Callback thread completes");

    66             callbackThreadCompleted.release();

    67         }

    68     };

    69 

    70     public static void main(String[] args) throws Exception {

    71         // Also test that we can shorten the lease from its initial value.

    72         leaseManager = new LeaseManager(triggerDeadlock, 1000000);

    73         leaseManager.lease(1L);

    74 

    75         boolean callbackRan =

    76                 callbackThreadCompleted.tryAcquire(3, TimeUnit.SECONDS);

    77 

    78         if (!callbackRan) {

    79             fail("Callback did not complete - probable deadlock");

    80             ThreadMXBean threads = ManagementFactory.getThreadMXBean();

    81             System.out.println(Arrays.toString(threads.findDeadlockedThreads()));

    82             System.out.println("PRESS RETURN");

    83             System.in.read();

    84         }

    85 

    86         if (failure == null)

    87             System.out.println("TEST PASSED");

    88         else

    89             throw new Exception("TEST FAILED: " + failure);

    90     }

    91 

    92     public static void fail(String why) {

    93         System.out.println("TEST FAILS: " + why);

    94         failure = why;

    95     }

    96 }