1 /*
   2  * Copyright (c) 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 8019623
  27  * @summary Tests that AppContext.getAppContext() works correctly in multi-threads scenario.
  28  * @author Leonid Romanov
  29  */
  30 
  31 import sun.awt.AppContext;
  32 
  33 public class MultiThreadTest {
  34     private static final int NUM_THREADS = 2;
  35 
  36     private static AppContextGetter[] getters = new AppContextGetter[NUM_THREADS];
  37 
  38     public static void main(String[] args) {
  39         createAndStartThreads();
  40         compareAppContexts();
  41     }
  42 
  43     private static void createAndStartThreads() {
  44         ThreadGroup systemGroup = getSystemThreadGroup();
  45         for (int i = 0; i < NUM_THREADS; ++i) {
  46             ThreadGroup tg = new ThreadGroup(systemGroup, "AppContextGetter" + i);
  47             getters[i] = new AppContextGetter(tg);
  48         }
  49 
  50         for (int i = 0; i < NUM_THREADS; ++i) {
  51             getters[i].start();
  52         }
  53 
  54         for (int i = 0; i < NUM_THREADS; ++i) {
  55             try {
  56                 getters[i].join();
  57             } catch (InterruptedException e) {
  58                 // ignore
  59             }
  60         }
  61     }
  62 
  63     private static ThreadGroup getSystemThreadGroup() {
  64         ThreadGroup currentThreadGroup =
  65                 Thread.currentThread().getThreadGroup();
  66         ThreadGroup parentThreadGroup = currentThreadGroup.getParent();
  67         while (parentThreadGroup != null) {
  68             currentThreadGroup = parentThreadGroup;
  69             parentThreadGroup = currentThreadGroup.getParent();
  70         }
  71 
  72         return currentThreadGroup;
  73     }
  74 
  75     private static void compareAppContexts() {
  76         AppContext ctx = getters[0].getAppContext();
  77         for (int i = 1; i < NUM_THREADS; ++i) {
  78             if (!ctx.equals(getters[i].getAppContext())) {
  79                 throw new RuntimeException("Unexpected AppContexts difference, could be a race condition");
  80             }
  81         }
  82     }
  83 
  84     private static class AppContextGetter extends Thread {
  85         private AppContext appContext;
  86 
  87         public AppContextGetter(ThreadGroup tg) {
  88             super(tg, tg.getName());
  89         }
  90 
  91         AppContext getAppContext() {
  92             return appContext;
  93         }
  94 
  95         @Override
  96         public void run() {
  97             appContext = AppContext.getAppContext();
  98         }
  99     }
 100 }