Hi ,
will JbossAs 4.2.3 GA supports RESTEasy?? if supports means what are configuration i need to do it?
You can use resteasy on jboss 4.2.3.GA.
Have a look at the manual for how to do the configuration
http://docs.jboss.org/resteasy/docs/2.0.0.GA/userguide/html/Installation_Configuration.html