threadPool = new PooledExecutor();
threadPool = new PooledExecutor(new LinkedQueue(), 10);
   public synchronized void start() throws Exception   {      if (started)      {         return;      }      log.debug(this + " starting");      mbeanServer = findMBeanServer();      tm = findTransactionManager();      // TODO: this should be configurable            pm = new HSQLDBPersistenceManager();           // TODO: is should be possible to share this with other peers      ms = new PersistentMessageStore(serverPeerID, pm, tm);      clientManager = new ClientManager(this);      destinationManager = new DestinationManagerImpl(this);      threadPool = new PooledExecutor();      initializeRemoting();      initializeAdvisors();      mbeanServer.registerMBean(destinationManager, DESTINATION_MANAGER_OBJECT_NAME);            securityManager.init();            setupConnectionFactories();      started = true;      log.info("JMS " + this + " started");   }