I got it. I removed the exception by deleting my jsf realted jars i.e. jsf-api and jsf-impl jars from my war since, jboss 4.2 GA web deployer itself contains these jar files under jsf-libs folder. But now I am getting a new problem that is I am unable to find a way to declare a context fro my webapp. [TomcatDeployer] deploy, ctxPath=/myapp, warUrl=.../tmp/deploy/tmp56381myapp-exp.war/ [config] Unable to process deployment descriptor for context 'null' It doesn't deploy my webapp and I am unable to run it. Please help me in finding some solutions to it. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4058556#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...