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();
         }
       }
     }
   }
 }