Document base/ Document root

[Michael Gesundheit]

Hi,
I have a problem which assume has to do with my document base.My environmet is 
Jboss.I keep getting the 404 page always saying the the page:"AppName/whatever" 
is not found.AppName is my servlet context.
I'm unable to determine my document base.Question: Is the a way in which I can 
find what does the internal TomCat sees as document base?Or is there a way to 
force TomCat to use a specific directory as the doc root?
Any advice will be appreciated.
Thanks,-Michael