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 8014477
  27  * @summary test String.contentEquals(StringBuffer)
  28  */
  29 public class StringContentEqualsBug {
  30 
  31     static class Task extends Thread {
  32         volatile StringBuffer sb;
  33         volatile Exception exception;
  34 
  35         Task(StringBuffer sb) {
  36             this.sb = sb;
  37         }
  38 
  39         @Override
  40         public void run() {
  41             try {
  42                 StringBuffer sb;
  43                 while ((sb = this.sb) != null) {
  44                     "QQ".contentEquals(sb);
  45                     sb.setLength(0);
  46                     sb.trimToSize();
  47                     sb.append("AA");
  48                 }
  49             }
  50             catch (Exception e) {
  51                 exception = e;
  52             }
  53         }
  54     }
  55 
  56     public static void main(String[] args) throws Exception {
  57         StringBuffer sb = new StringBuffer();
  58         Task[] tasks = new Task[3];
  59         for (int i = 0; i < tasks.length; i++) {
  60             (tasks[i] = new Task(sb)).start();
  61         }
  62         try
  63         {
  64             // wait at most 5 seconds for any of the threads to throw exception
  65             for (int i = 0; i < 20; i++) {
  66                 for (Task task : tasks) {
  67                     if (task.exception != null) {
  68                         throw task.exception;
  69                     }
  70                 }
  71                 Thread.sleep(250L);
  72             }
  73         }
  74         finally {
  75             for (Task task : tasks) {
  76                 task.sb = null;
  77                 task.join();
  78             }
  79         }
  80     }
  81 }