UrlRewriteFilter
Based on the popular and very useful mod_rewrite for apache, UrlRewriteFilter is a Java Web Filter for any J2EE compliant web application server (such as Resin, Orion or Tomcat), which allows you to rewrite URLs before they get to your code. It is a very powerful tool just like Apache's mod_rewrite.
More on the main web site.
General Tips for debugging UrlRewriteFilter:
If you think you have found a bug: