public synchronized Collection<GarbageCollectorMXBean> getGarbageCollectorMXBeans()
throws IOException {
// TODO: How to deal with changes to the list??
if (garbageCollectorMBeans == null) {
ObjectName gcName = null;
try {
gcName = new ObjectName(GARBAGE_COLLECTOR_MXBEAN_DOMAIN_TYPE + ",*");
} catch (MalformedObjectNameException e) {
// should not reach here
assert (false);
}
Set<ObjectName> mbeans = server.queryNames(gcName, null);
if (mbeans != null) {
garbageCollectorMBeans = new ArrayList<GarbageCollectorMXBean>();
Iterator<ObjectName> iterator = mbeans.iterator();
while (iterator.hasNext()) {
ObjectName on = (ObjectName) iterator.next();
String name = GARBAGE_COLLECTOR_MXBEAN_DOMAIN_TYPE + ",name=" + on.getKeyProperty("name");
GarbageCollectorMXBean mBean =
newPlatformMXBeanProxy(server, name, GarbageCollectorMXBean.class);
garbageCollectorMBeans.add(mBean);
}
}
}
return garbageCollectorMBeans;
}
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 checkPlatformMBeans() throws Exception {
MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
Set<ObjectName> mbeanNames = mbs.queryNames(null, null);
for (ObjectName name : mbeanNames) {
if (!mbs.isInstanceOf(name, NotificationBroadcaster.class.getName())) {
System.out.println(name + ": not a NotificationBroadcaster");
} else {
MBeanInfo mbi = mbs.getMBeanInfo(name);
check(name.toString(), mbi.getNotifications());
}
}
}
public <T> T getMXBean(ObjectName objName, Class<T> interfaceClass) throws IOException {
return newPlatformMXBeanProxy(server, objName.toString(), interfaceClass);
}