static MBeanServer start(){
  if (!isStarted) {
    mbeanServer=createMBeanServer();
    registry=createRegistry();
    registerServerNotificationListener();
    createRefreshTimer();
    isStarted=true;
  }
  return mbeanServer;
}

static MBeanServer start ( ) { if ( ! isStarted ) { mbeanServer = createMBeanServer ( ) ; registry = createRegistry ( ) ; registerServerNotificationListener ( ) ; createRefreshTimer ( ) ; isStarted = true ; } return mbeanServer ; }
initializes mbean server , registry , refresh timer & registers server notification listener .
