1 /*
   2  * Copyright (c) 2007, 2011, 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  * This test is relatively useful for verifying 6379235, but
  26  * is too resource intensive, especially on 64 bit systems,
  27  * to be run automatically, see 6721694.
  28  *
  29  * When run it should be typically be run with the server vm
  30  * and a relatively small java heap, and a large stack size
  31  * ( to provoke the OOM quicker ).
  32  *    java -server -Xmx32m -Xms32m -Xss256m StartOOMTest
  33  */
  34 
  35 import java.util.*;
  36 
  37 public class StartOOMTest
  38 {
  39     public static void main(String[] args) throws Throwable {
  40         Runnable r = new SleepRunnable();
  41         ThreadGroup tg = new ThreadGroup("buggy");
  42         List<Thread> threads = new ArrayList<Thread>();
  43         Thread failedThread;
  44         int i = 0;
  45         for (i = 0; ; i++) {
  46             Thread t = new Thread(tg, r);
  47             try {
  48                 t.start();
  49                 threads.add(t);
  50             } catch (Throwable x) {
  51                 failedThread = t;
  52                 System.out.println(x);
  53                 System.out.println(i);
  54                 break;
  55             }
  56         }
  57 
  58         int j = 0;
  59         for (Thread t : threads)
  60             t.interrupt();
  61 
  62         while (tg.activeCount() > i/2)
  63             Thread.yield();
  64         failedThread.start();
  65         failedThread.interrupt();
  66 
  67         for (Thread t : threads)
  68             t.join();
  69         failedThread.join();
  70 
  71         try {
  72             Thread.sleep(1000);
  73         } catch (Throwable ignore) {
  74         }
  75 
  76         int activeCount = tg.activeCount();
  77         System.out.println("activeCount = " + activeCount);
  78 
  79         if (activeCount > 0) {
  80             throw new RuntimeException("Failed: there  should be no active Threads in the group");
  81         }
  82     }
  83 
  84     static class SleepRunnable implements Runnable
  85     {
  86         public void run() {
  87             try {
  88                 Thread.sleep(60*1000);
  89             } catch (Throwable t) {
  90             }
  91         }
  92     }
  93 }