In configuration with a front Apache HTTPd 2.2.x server and backend Tomcat servers, you may have defined customs error page on the HTTPd configuration using ErrorDocument directive.

ErrorDocument 401 /errors/err-401.html ErrorDocument 403 /errors/err-403.html ErrorDocument 404 /errors/err-404.html ErrorDocument 500 /errors/err-500.html ```

It works well for resources handled by HTTPd but errors for contents served by Tomcat are still handled by Tomcat error mecanism.

Imagine a web application myapp, served by a Tomcat behind HTTPd, you could have the following setup.

JkMount /myapp/* worker1

If someone hit an inexisting page, ie /myapp/myfaultypage, you’ll get back the 404 error from Tomcat but not the one defined in HTTPd.

Since version 1.2.27, mod_jk could handle such situation via uriworkermap use_server_errors directive.

But if you don’t want to change your current setup, ie using JkMount, you could use the following :

JkMount /myapp/* worker1;use_server_errors=400

If Tomcat allready handle Page Not Found, 404, and you only wan’t to see Apache HTTPd handling error greater than or egal to 500, just use :

JkMount /myapp/* worker1;use_server_errors=500

Thanks to Mladen for the trick :)