test/java/lang/ThreadGroup/Suspend.java

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   1 /*
   2  * Copyright (c) 1999, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 /**
  25  * @test
  26  * @bug 4176355
  27  * @summary Suspending a ThreadGroup that contains the current thread has
  28  *          unpredictable results.
  29  */
  30 



  31 public class Suspend implements Runnable {
  32     private static Thread first=null;
  33     private static Thread second=null;
  34     private static ThreadGroup group = new ThreadGroup("");
  35     private static int count = 0;
  36 
  37     Suspend() {
  38         Thread thread = new Thread(group, this);
  39         if (first == null)
  40             first = thread;
  41         else
  42             second = thread;
  43 
  44         thread.start();
  45     }





  46 
  47     public void run() {

  48         while (true) {
  49             try {
  50                 Thread.sleep(1000); // Give other thread a chance to start
  51                 if (Thread.currentThread() == first)
  52                     group.suspend();
  53                 else
  54                     count++;
  55             } catch(InterruptedException e){


  56             }
  57         }
  58     }
  59 
  60     public static void main(String[] args) throws Exception {
  61         for (int i=0; i<2; i++)
  62             new Suspend();
  63         Thread.sleep(3000);
  64         boolean failed = (count > 1);
  65         first.stop(); second.stop();










  66         if (failed)
  67             throw new RuntimeException("Failure.");
  68     }
  69 }
   1 /*
   2  * Copyright (c) 1999, 2013 Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 /**
  25  * @test
  26  * @bug 4176355 7181748
  27  * @summary Suspending a ThreadGroup that contains the current thread has
  28  *          unpredictable results.
  29  */
  30 
  31 import java.util.concurrent.CountDownLatch;
  32 import java.util.concurrent.TimeUnit;
  33 
  34 public class Suspend implements Runnable {











  35 
  36     private static final ThreadGroup group = new ThreadGroup("");
  37     private static final Thread first = new Thread(group, new Suspend());
  38     private static final Thread second = new Thread(group, new Suspend());
  39     private static final CountDownLatch groupStarted = new CountDownLatch(2);
  40     private static final CountDownLatch runGroup = new CountDownLatch(1);
  41     private static final CountDownLatch secondContinue = new CountDownLatch(1);
  42     private static final CountDownLatch secondDone = new CountDownLatch(1);
  43 
  44     public void run() {
  45         groupStarted.countDown();
  46         while (true) {
  47             try {
  48                 runGroup.await();
  49                 if (Thread.currentThread() == first) {
  50                     group.suspend();
  51                 } else {
  52                     secondContinue.await();
  53                     secondDone.countDown(); // should never be executed
  54                 }
  55             } catch (InterruptedException ex) {
  56             }
  57         }
  58     }
  59 
  60     public static void main(String[] args) throws Exception {
  61         // Launch two threads as part of the same thread group
  62         first.start();
  63         second.start();
  64 
  65         groupStarted.await();
  66         runGroup.countDown();
  67         Thread.sleep(1000);
  68         // Suppose, the thread group is now suspended
  69 
  70         secondContinue.countDown();
  71 
  72         // Reaching zero count indicates that the second thread is still running
  73         boolean failed = secondDone.await(1L, TimeUnit.SECONDS);
  74         first.stop();
  75         second.stop();
  76         if (failed)
  77             throw new RuntimeException("Failure.");
  78     }
  79 }