Handling Page Not Found using struts

While surfing web, Most of us have encountered 404- Page not found message. Any resource you request; If it does not exist on server you would get such an error. In struts applications when you request for x.do and if there is no Action-mapping defined in struts-config.xml file for ActionForward x; You would get such an error.

Unknown ActionMapping

In struts you can define one ActionMapping which will receive all requests for which no ActionMappins is defined. It is called "Unknown ActionMapping".

name="/debug"
unknown="true"
forward="/pages/debug.jsp/>

Notably one can also do some NLP or spell correction to seek for resource user might be looking for and can ask to give that resource. This helps improving user experience while surfing your site.