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<String>();
    for (Map.Entry entry : usage.entrySet()) {
      String poolname = (String) entry.getKey();
      pnames.add(poolname);
      MemoryUsage busage = (MemoryUsage) entry.getValue();
      MemoryUsage ausage = (MemoryUsage) info.getMemoryUsageAfterGc().get(poolname);
      if (ausage == null) {
        throw new RuntimeException("After Gc Memory does not exist" + " for " + poolname);
      }
      System.out.println("Usage for pool " + poolname);
      System.out.println("   Before GC: " + busage);
      System.out.println("   After GC: " + ausage);
    }

    // check if memory usage for all memory pools are returned
    List<MemoryPoolMXBean> pools = ManagementFactory.getMemoryPoolMXBeans();
    for (MemoryPoolMXBean p : pools) {
      if (!pnames.contains(p.getName())) {
        throw new RuntimeException(
            "GcInfo does not contain " + "memory usage for pool " + p.getName());
      }
    }
  }
 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");
 }