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"); }
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(); } } } } }