title: Servlet 3.0 Async-supported does not work
body: <p>Here is my web.xml</p>
  
  <pre><code>    &lt;filter&gt;
      &lt;filter-name&gt;pollingTest&lt;/filter-name&gt;
      &lt;filter-class&gt;
          webapp.controller.core.servlet.PollingService
              &lt;/filter-class&gt;
      &lt;async-supported&gt;true&lt;/async-supported&gt;
  &lt;/filter&gt;
  &lt;filter-mapping&gt;
      &lt;filter-name&gt;pollingTest&lt;/filter-name&gt;
      &lt;url-pattern&gt;/app/poll&lt;/url-pattern&gt;
      &lt;dispatcher&gt;REQUEST&lt;/dispatcher&gt;
      &lt;dispatcher&gt;FORWARD&lt;/dispatcher&gt;
      &lt;dispatcher&gt;ASYNC&lt;/dispatcher&gt;
  &lt;/filter-mapping&gt;
  </code></pre>
  
  <p>Here is the class:</p>
  
  <pre><code>public class PollingService implements Filter {
  Logger logger = LoggerFactory.getLogger(getClass());
  
  @Override
  public void destroy() {
      logger.info("Destroy");
  }
  
  @Override
  public void doFilter(ServletRequest req, ServletResponse res,
          FilterChain chain) throws IOException, ServletException {
  
      logger.info("Running");
      req.startAsync(req, res);
      this.doFilter(req, res, chain);
      return;
  }
  
  @Override
  public void init(FilterConfig arg0) throws ServletException {
  
      logger.info("Init=");
  }
  </code></pre>
  
  <p>}</p>
  
  <p>I run it on glassfish and also on tomcat 7, got exception:</p>
  
  <pre><code>java.lang.IllegalStateException: Request is within the scope of a filter or servlet that does not support asynchronous operations
  at org.apache.catalina.connector.Request.startAsync(Request.java:3657)
  at org.apache.catalina.connector.Request.startAsync(Request.java:3633)
  at org.apache.catalina.connector.RequestFacade.startAsync(RequestFacade.java:1053)
  at javax.servlet.ServletRequestWrapper.startAsync(ServletRequestWrapper.java:450)
  </code></pre>
  
  <p>Who can help me on this? thanks a lot.</p>