Monitorear Errores en Tomcat

Tomado de:

http://wiki.apache.org/tomcat/FAQ/Miscellaneous#Q3

How do I get a customized error page?

In web.xml ...

       
           404
           /error/404.html
       

You may also catch error 500's as well as other specific exceptions or exceptions which extend Throwable. For more information, see the Servlet Specification for all the gory details of how you can play with this.