public static void registerMBean(ObjectName objectName, Object mbean) {
final MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
if (mbs.isRegistered(objectName)) {
try {
LOG.info("unregister: "+objectName);
mbs.unregisterMBean(objectName);
} catch (InstanceNotFoundException e) {
throw new IllegalStateException("mbean " + objectName +
" failed unregistration", e);
} catch (MBeanRegistrationException e) {
throw new IllegalStateException("mbean " + objectName +