1 /*
   2  * Copyright (c) 2013, 2015 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 7105883
  27  *  @summary Ensure that JDWP doesn't crash with a null thread group name
  28  *
  29  *  @modules jdk.jdi
  30  *  @run build TestScaffold VMConnection TargetListener TargetAdapter
  31  *  @run driver NullThreadGroupNameTest
  32  */
  33 import com.sun.jdi.*;
  34 import com.sun.jdi.connect.*;
  35 import com.sun.jdi.event.*;
  36 import com.sun.jdi.request.*;
  37 import com.sun.jdi.VMDisconnectedException;
  38 import java.util.concurrent.CountDownLatch;
  39 import java.util.*;
  40 
  41 class DebugTarget {
  42     public final static String DEBUG_THREAD_NAME = "DebugThread";
  43 
  44     public static void main(String[] args) throws Exception {
  45         DebugThread thread = new DebugThread();
  46         thread.start();
  47         thread.runningLatch.await();
  48         breakpointHere();
  49         thread.breakpointLatch.countDown();
  50     }
  51 
  52     public static void breakpointHere() {
  53         System.out.println("Breakpoint finished!");
  54     }
  55 
  56     static class DebugThread extends Thread {
  57         final CountDownLatch runningLatch = new CountDownLatch(1);
  58         final CountDownLatch breakpointLatch = new CountDownLatch(1);
  59 
  60         public DebugThread() {
  61             super(new ThreadGroup(null), DEBUG_THREAD_NAME);
  62         }
  63 
  64         public void run() {
  65             runningLatch.countDown();
  66             try {
  67                 breakpointLatch.await();
  68             } catch (InterruptedException ie) {
  69                 ie.printStackTrace();
  70             }
  71         }
  72     }
  73 }
  74 
  75 public class NullThreadGroupNameTest extends TestScaffold {
  76 
  77     NullThreadGroupNameTest(String args[]) {
  78         super(args);
  79     }
  80 
  81     public static void main(String[] args) throws Exception {
  82         new NullThreadGroupNameTest(args).startTests();
  83     }
  84 
  85     protected void runTests() throws Exception {
  86         startTo("DebugTarget", "breakpointHere", "()V");
  87 
  88         ThreadReference thread = findThread(DebugTarget.DEBUG_THREAD_NAME);
  89         assertThreadGroupName(thread.threadGroup(), "");
  90 
  91         listenUntilVMDisconnect();
  92     }
  93 
  94     private ThreadReference findThread(String name) {
  95         for (ThreadReference thread : vm().allThreads()) {
  96             if (name.equals(thread.name())) {
  97                 return thread;
  98             }
  99         }
 100         throw new NoSuchElementException("Couldn't find " + name);
 101     }
 102 
 103     private void assertThreadGroupName(ThreadGroupReference threadGroup, String expectedName) {
 104         try {
 105             String name = threadGroup.name();
 106             if (!expectedName.equals(name)) {
 107                 throw new AssertionError("Unexpected thread group name '" + name + "'");
 108             }
 109         } catch (VMDisconnectedException vmde) {
 110             throw new AssertionError("Likely JVM crash with null thread group name", vmde);
 111         }
 112     }
 113 }