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();
}
}
}
}
}