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 abstract 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                     doWith(sb);

    45                 }

    46             }

    47             catch (Exception e) {

    48                 exception = e;

    49             }

    50         }

    51 

    52         protected abstract void doWith(StringBuffer sb);

    53     }

    54 

    55     static class Tester extends Task {

    56         Tester(StringBuffer sb) {

    57             super(sb);

    58         }

    59 

    60         @Override

    61         protected void doWith(StringBuffer sb) {

    62             "AA".contentEquals(sb);

    63         }

    64     }

    65 

    66     static class Disturber extends Task {

    67         Disturber(StringBuffer sb) {

    68             super(sb);

    69         }

    70 

    71         @Override

    72         protected void doWith(StringBuffer sb) {

    73             sb.setLength(0);

    74             sb.trimToSize();

    75             sb.append("AA");

    76         }

    77     }

    78 

    79 

    80     public static void main(String[] args) throws Exception {

    81         StringBuffer sb = new StringBuffer();

    82         Task[] tasks = new Task[3];

    83         (tasks[0] = new Tester(sb)).start();

    84         for (int i = 1; i < tasks.length; i++) {

    85             (tasks[i] = new Disturber(sb)).start();

    86         }

    87 

    88         try

    89         {

    90             // wait at most 5 seconds for any of the threads to throw exception

    91             for (int i = 0; i < 20; i++) {

    92                 for (Task task : tasks) {

    93                     if (task.exception != null) {

    94                         throw task.exception;

    95                     }

    96                 }

    97                 Thread.sleep(250L);

    98             }

    99         }

   100         finally {

   101             for (Task task : tasks) {

   102                 task.sb = null;

   103                 task.join();

   104             }

   105         }

   106     }

   107 }