Задача Async сервлета 3 на Tomcat 7

Я пытаюсь реализовать простой чат с использованием шаблона Servlet 3.0 и Comet на основе его поддержки асинхронности.

Меня вдохновила эта статья: http://www.javaworld.com/javaworld/jw-02-2009/jw-02-servlet3.html?page=3

Мой сервлет выглядит так.

@WebServlet(name="chatServlet", urlPatterns={"/ChatServlet"}, asyncSupported=true)
public class ChatServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         AsyncContext aCtx = request.startAsync(request, response); 
         ServletContext appScope = request.getServletContext();    
         List watchers = (List) appScope.getAttribute("watchers");
         watchers.add(aCtx); //register the watcher
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
          AsyncContext aCtx = request.startAsync(request, response); 
          ServletContext appScope = request.getServletContext(); 
          Queue messages = (Queue)appScope.getAttribute("messages");
          messages.add(someMessage);
    }
} 

Теперь мой Listener выглядит так:

@WebListener
public class ChatPushService implements ServletContextListener {

        @Override
        public void contextInitialized(ServletContextEvent sce) {
              final List watchers = new  ArrayList();
             sce.getServletContext().setAttribute("watchers", watchers);
              // store new messages not published yet
             Queue messages = new ConcurrentLinkedQueue();
             sce.getServletContext().setAttribute("messages", messages);
             Executor messageExecutor = Executors.newCachedThreadPool(); 
             final Executor watcherExecutor = Executors.newCachedThreadPool();
             while(true)
              {      

                 if(!messages.isEmpty()) 
                 {
                     System.out.println("notEmpty");
                    String message =  messages.poll(); 
                    messageExecutor.execute(new Runnable(){

                        @Override
                        public void run() {
                             for(final AsyncContext aCtx : watchers){
                                 watcherExecutor.execute(new Runnable(){

                                     @Override
                                        public void run() {
                                           try {
                                            aCtx.getResponse().getWriter().print("brrrrr");
                                        } catch (IOException e) {
                                            // TODO Auto-generated catch block
                                            e.printStackTrace();
                                        }
                                     }
                                 });
                             }
                        }
                 });
              }
        }

    }
    }

Когда я запускаю, он зависает во время запуска контейнера.

Nov 1, 2011 1:12:09 AM org.apache.catalina.core.AprLifecycleListener init
INFO: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/server:/usr/lib/jvm/java-6-openjdk/jre/lib/amd64:/usr/lib/jvm/java-6-openjdk/jre/../lib/amd64:/usr/java/packages/lib/amd64:/usr/lib/jni:/lib:/usr/lib
Nov 1, 2011 1:12:09 AM org.apache.tomcat.util.digester.SetPropertiesRule begin
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:Servlet3Comet' did not find a matching property.
Nov 1, 2011 1:12:09 AM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-bio-8080"]
Nov 1, 2011 1:12:09 AM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["ajp-bio-8009"]
Nov 1, 2011 1:12:09 AM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 624 ms
Nov 1, 2011 1:12:09 AM org.apache.catalina.core.StandardService startInternal
INFO: Starting service Catalina
Nov 1, 2011 1:12:09 AM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/7.0.22

Похоже, что функция public void contextInitialized не работает асинхронно в фоновом режиме и блокирует дальнейшую инициализацию контейнера.

Почему?

Кто-нибудь может мне помочь в этом вопросе?