title: What is an 'error dispatch' in servlet processing?
body: <p>The <a href="http://docs.oracle.com/javaee/6/api/javax/servlet/AsyncContext.html" rel="nofollow noreferrer">javadoc of the javax.servlet.AsyncContext interface</a> says:</p>
  
  <blockquote>
    <p>In the event that an asynchronous operation has timed out, the
    container must run through these steps:</p>
    
    <ul>
    <li>Invoke, at their <code>onTimeout</code> method, all <code>AsyncListener</code> instances    registered with the <code>ServletRequest</code> on which the asynchronous<br>
    operation was initiated. </li>
    <li>If none of the listeners called <code>complete()</code>    or any of the <code>dispatch()</code> methods, perform an error dispatch with a    status code
    equal to <code>HttpServletResponse.SC_INTERNAL_SERVER_ERROR</code>. </li>
    <li>If no matching error page was found, or the error page did not call    <code>complete()</code> or any of the <code>dispatch()</code> methods, call <code>complete()</code>.</li>
    </ul>
  </blockquote>
  
  <p>But I couldn't find the meaning of "error dispatch" anywhere.
  In fact there was an <a href="https://issues.apache.org/bugzilla/show_bug.cgi?id=54123" rel="nofollow noreferrer">Apache bug</a> that exclaimed the same. (In their exact words: "I haven't seen the def. of 'error dispatch', too")</p>
  
  <p>But of course, there must be a clear definition for this and how to use it.
  Does anyone know?</p>