title: Debug Tomcat Application Startup
body: <p>Normally, my instance of Tomcat starts-up without any problem. However, when I add a new filter to the 'preview' web app, that application fails to start:</p>
  
  <pre><code>09-Jun-2011 12:23:49 org.apache.catalina.core.StandardContext start
  SEVERE: Error filterStart
  09-Jun-2011 12:23:49 org.apache.catalina.core.StandardContext start
  SEVERE: Context [] startup failed due to previous errors
  09-Jun-2011 12:23:49 com.polopoly.application.StandardApplication destroy
  INFO: Application 'preview' destroy started.
  </code></pre>
  
  <p>Tomcat itself starts fine - other wars / web apps deploy and start as normal.</p>
  
  <p>As there's no stack trace in the log, I'm not exactly sure what the issue is. I can't connect a remote debugger to the app because it's not running any more. Can I place breakpoints at the init of the app or filter?</p>
  
  <p>What is the best approach / preferred method for debugging issues during the start-up of a web application in Tomcat?</p>