1 /*
   2  * Copyright (c) 2005, 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 6305746
  27  * @key randomness
  28  * @summary Test that the null values returned by the ThreadMXBean work.
  29  * @author Eamonn McManus
  30  *
  31  * @run clean ThreadMXBeanTest
  32  * @run build ThreadMXBeanTest
  33  * @run main ThreadMXBeanTest
  34  */
  35 
  36 import java.lang.management.*;
  37 import java.util.*;
  38 import javax.management.*;
  39 
  40 public class ThreadMXBeanTest {
  41     public static void main(String[] args) throws Exception {
  42         MBeanServer mbs = MBeanServerFactory.newMBeanServer();
  43         ThreadMXBean tmb = ManagementFactory.getThreadMXBean();
  44         StandardMBean smb = new StandardMBean(tmb, ThreadMXBean.class, true);
  45         ObjectName on = new ObjectName("a:type=ThreadMXBean");
  46         mbs.registerMBean(smb, on);
  47         ThreadMXBean proxy = JMX.newMXBeanProxy(mbs, on, ThreadMXBean.class);
  48         long[] ids1 = proxy.getAllThreadIds();
  49 
  50         // Add some random ids to the list so we'll get back null ThreadInfo
  51         long[] ids2 = new long[ids1.length + 10];
  52         System.arraycopy(ids1, 0, ids2, 0, ids1.length);
  53         Random r = new Random();
  54         for (int i = ids1.length; i < ids2.length; i++)
  55             ids2[i] = Math.abs(r.nextLong());
  56         // Following line produces an exception if null values not handled
  57         ThreadInfo[] info = proxy.getThreadInfo(ids2);
  58         boolean sawNull = false;
  59         for (ThreadInfo ti : info) {
  60             if (ti == null)
  61                 sawNull = true;
  62         }
  63         if (!sawNull)
  64             throw new Exception("No null value in returned array");
  65         System.out.println("TEST PASSED");
  66     }
  67 }