1 /*
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   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     4858522
  27  * @summary Basic unit test of HotspotClassLoadingMBean.getSafepointCount()
  28  * @author  Steve Bohne
  29  * @modules java.management/sun.management
  30  * @run main/othervm -XX:+UsePerfData GetSafepointCount
  31  */
  32 
  33 /*
  34  * This test is just a sanity check and does not check for the correct value.
  35  */
  36 
  37 import sun.management.*;
  38 
  39 public class GetSafepointCount {
  40 
  41     private static HotspotRuntimeMBean mbean =
  42         (HotspotRuntimeMBean)ManagementFactoryHelper.getHotspotRuntimeMBean();
  43 
  44     private static final long NUM_THREAD_DUMPS = 5;
  45 
  46     // Careful with these values.
  47     private static final long MIN_VALUE_FOR_PASS = NUM_THREAD_DUMPS;
  48     private static final long MAX_VALUE_FOR_PASS = Long.MAX_VALUE;
  49 
  50     private static boolean trace = false;
  51 
  52     public static void main(String args[]) throws Exception {
  53         if (args.length > 0 && args[0].equals("trace")) {
  54             trace = true;
  55         }
  56 
  57         // Thread.getAllStackTraces() should cause safepoints.
  58         // If this test is failing because it doesn't,
  59         // MIN_VALUE_FOR_PASS should be reset to 0
  60         for (int i = 0; i < NUM_THREAD_DUMPS; i++) {
  61             Thread.getAllStackTraces();
  62         }
  63 
  64         long value = mbean.getSafepointCount();
  65 
  66         if (trace) {
  67             System.out.println("Safepoint count: " + value);
  68         }
  69 
  70         if (value < MIN_VALUE_FOR_PASS || value > MAX_VALUE_FOR_PASS) {
  71             throw new RuntimeException("Safepoint count " +
  72                                        "illegal value: " + value + " " +
  73                                        "(MIN = " + MIN_VALUE_FOR_PASS + "; " +
  74                                        "MAX = " + MAX_VALUE_FOR_PASS + ")");
  75         }
  76 
  77         for (int i = 0; i < NUM_THREAD_DUMPS; i++) {
  78             Thread.getAllStackTraces();
  79         }
  80 
  81         long value2 = mbean.getSafepointCount();
  82 
  83         if (trace) {
  84             System.out.println("Safepoint count2: " + value2);
  85         }
  86 
  87         if (value2 <= value) {
  88             throw new RuntimeException("Safepoint count " +
  89                                        "did not increase " +
  90                                        "(value = " + value + "; " +
  91                                        "value2 = " + value2 + ")");
  92         }
  93 
  94         System.out.println("Test passed.");
  95     }
  96 }