title: Best way to catch all unhandled exceptions in all Tomcat (GWT) servlets
body: <p>I use Tomcat 7 and Lo4j for all my server logs and GWT for client (only AJAX calls).
  All my unhandled exceptions get logged in my catalina.log.</p>
  
  <p>Now I want to catch all exceptions and add some of the user's specific Tomcat SessionData.</p>
  
  <p>There are several ways:</p>
  
  <ul>
  <li>Try catch over all servlets (there must be a better solution).</li>
  <li><a href="http://tomcat.apache.org/tomcat-7.0-doc/aio.html" rel="nofollow">http://tomcat.apache.org/tomcat-7.0-doc/aio.html</a>: I would have to change my connecter, and I don't know if I could use the Tomcat Session within the Event Handler (EventType.ERROR).</li>
  <li>Better way?</li>
  </ul>
  
  <p>What would be the best way to achieve this?</p>