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
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22  */
23 
24 /**
25  * @test
26  * @bug 7105883
27  * @summary Ensure that JDWP doesn't crash with a null thread group name
28  *
29  * @run build TestScaffold VMConnection TargetListener TargetAdapter
30  * @run driver NullThreadGroupNameTest
31  */
32 import com.sun.jdi.*;
33 import com.sun.jdi.connect.*;
34 import com.sun.jdi.event.*;
35 import com.sun.jdi.request.*;
36 import com.sun.jdi.VMDisconnectedException;
37 import java.util.concurrent.CountDownLatch;
38 import java.util.*;
39 
40 class DebugTarget {
41     public final static String DEBUG_THREAD_NAME = "DebugThread";
42 
main(String[] args)43     public static void main(String[] args) throws Exception {
44         DebugThread thread = new DebugThread();
45         thread.start();
46         thread.runningLatch.await();
47         breakpointHere();
48         thread.breakpointLatch.countDown();
49     }
50 
breakpointHere()51     public static void breakpointHere() {
52         System.out.println("Breakpoint finished!");
53     }
54 
55     static class DebugThread extends Thread {
56         final CountDownLatch runningLatch = new CountDownLatch(1);
57         final CountDownLatch breakpointLatch = new CountDownLatch(1);
58 
DebugThread()59         public DebugThread() {
60             super(new ThreadGroup(null), DEBUG_THREAD_NAME);
61         }
62 
run()63         public void run() {
64             runningLatch.countDown();
65             try {
66                 breakpointLatch.await();
67             } catch (InterruptedException ie) {
68                 ie.printStackTrace();
69             }
70         }
71     }
72 }
73 
74 public class NullThreadGroupNameTest extends TestScaffold {
75 
NullThreadGroupNameTest(String args[])76     NullThreadGroupNameTest(String args[]) {
77         super(args);
78     }
79 
main(String[] args)80     public static void main(String[] args) throws Exception {
81         new NullThreadGroupNameTest(args).startTests();
82     }
83 
runTests()84     protected void runTests() throws Exception {
85         startTo("DebugTarget", "breakpointHere", "()V");
86 
87         ThreadReference thread = findThread(DebugTarget.DEBUG_THREAD_NAME);
88         assertThreadGroupName(thread.threadGroup(), "");
89 
90         listenUntilVMDisconnect();
91     }
92 
findThread(String name)93     private ThreadReference findThread(String name) {
94         for (ThreadReference thread : vm().allThreads()) {
95             if (name.equals(thread.name())) {
96                 return thread;
97             }
98         }
99         throw new NoSuchElementException("Couldn't find " + name);
100     }
101 
assertThreadGroupName(ThreadGroupReference threadGroup, String expectedName)102     private void assertThreadGroupName(ThreadGroupReference threadGroup, String expectedName) {
103         try {
104             String name = threadGroup.name();
105             if (!expectedName.equals(name)) {
106                 throw new AssertionError("Unexpected thread group name '" + name + "'");
107             }
108         } catch (VMDisconnectedException vmde) {
109             throw new AssertionError("Likely JVM crash with null thread group name", vmde);
110         }
111     }
112 }
113