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Java example source code file (GarbageCollectionNotificationContentTest.java)
The GarbageCollectionNotificationContentTest.java Java example source code/* * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ /* * @test * @bug 7036199 * @summary Check that GarbageCollectionNotification contents are reasonable * @author Frederic Parain * @run main/othervm GarbageCollectionNotificationContentTest */ import java.util.*; import java.lang.management.*; import java.lang.reflect.*; import javax.management.*; import javax.management.openmbean.*; import com.sun.management.GarbageCollectionNotificationInfo; import com.sun.management.GcInfo; import java.security.AccessController; import java.security.PrivilegedAction; import java.lang.reflect.Field; public class GarbageCollectionNotificationContentTest { private static HashMap<String,GarbageCollectionNotificationInfo> listenerInvoked = new HashMap<String,GarbageCollectionNotificationInfo>(); static volatile long count = 0; static volatile long number = 0; static Object synchronizer = new Object(); static class GcListener implements NotificationListener { public void handleNotification(Notification notif, Object handback) { String type = notif.getType(); if (type.equals(GarbageCollectionNotificationInfo.GARBAGE_COLLECTION_NOTIFICATION)) { GarbageCollectionNotificationInfo gcNotif = GarbageCollectionNotificationInfo.from((CompositeData) notif.getUserData()); String source = ((ObjectName)notif.getSource()).getCanonicalName(); synchronized(synchronizer) { if(listenerInvoked.get(source) == null) { listenerInvoked.put(((ObjectName)notif.getSource()).getCanonicalName(),gcNotif); count++; if(count >= number) { synchronizer.notify(); } } } } } } public static void main(String[] args) throws Exception { MBeanServer mbs = ManagementFactory.getPlatformMBeanServer(); final Boolean isNotificationSupported = AccessController.doPrivileged (new PrivilegedAction<Boolean>() { public Boolean run() { try { Class cl = Class.forName("sun.management.VMManagementImpl"); Field f = cl.getDeclaredField("gcNotificationSupport"); f.setAccessible(true); return f.getBoolean(null); } catch(ClassNotFoundException e) { return false; } catch(NoSuchFieldException e) { return false; } catch(IllegalAccessException e) { return false; } } }); if(!isNotificationSupported) { System.out.println("GC Notification not supported by the JVM, test skipped"); return; } final ObjectName gcMXBeanPattern = new ObjectName("java.lang:type=GarbageCollector,*"); Set<ObjectName> names = mbs.queryNames(gcMXBeanPattern, null); if (names.isEmpty()) throw new Exception("Test incorrect: no GC MXBeans"); number = names.size(); for (ObjectName n : names) { if(mbs.isInstanceOf(n,"javax.management.NotificationEmitter")) { listenerInvoked.put(n.getCanonicalName(),null); GcListener listener = new GcListener(); mbs.addNotificationListener(n, listener, null, null); } } // Invocation of System.gc() to trigger major GC System.gc(); // Allocation of many short living and small objects to trigger minor GC Object data[] = new Object[32]; for(int i = 0; i<100000000; i++) { data[i%32] = new int[8]; } int wakeup = 0; synchronized(synchronizer) { while(count != number) { synchronizer.wait(10000); wakeup++; if(wakeup > 10) break; } } for (GarbageCollectionNotificationInfo notif : listenerInvoked.values() ) { checkGarbageCollectionNotificationInfoContent(notif); } System.out.println("Test passed"); } private static void checkGarbageCollectionNotificationInfoContent(GarbageCollectionNotificationInfo notif) throws Exception { System.out.println("GC notification for "+notif.getGcName()); System.out.print("Action: "+notif.getGcAction()); System.out.println(" Cause: "+notif.getGcCause()); GcInfo info = notif.getGcInfo(); System.out.print("GC Info #" + info.getId()); System.out.print(" start:" + info.getStartTime()); System.out.print(" end:" + info.getEndTime()); System.out.println(" (" + info.getDuration() + "ms)"); Map<String, MemoryUsage> usage = info.getMemoryUsageBeforeGc(); List<String> pnames = new ArrayList Other Java examples (source code examples)Here is a short list of links related to this Java GarbageCollectionNotificationContentTest.java source code file: |
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