I've added this post to a couple of other forums which might be relevant.
In particular I noticed the word "eclipse" in the error report. That suggests you might be running all of this in the Eclipse IDE. If that's the case then, in my experience, you get this kind of problem if the Eclipse project is misconfigured and it doesn't have a proper reference to a valid JDK.
Souvik Dasgupta wrote:
Even I thought that after going through the answer in different forums. But after I generate the WAR is it really relevant what IDE I am using?
Also, in the same Eclipse Workspace I have few other projects, which are deploying fine.
Well, the JSPs are compiled by JBoss at run time, so yes it could be relevant. And it does look like Eclipse is doing the compiling, based on the error message.
Also, each Eclipse project has its own configuration to say what JDK to use, so the fact that those projects don't have that kind of compiler error doesn't tell you much. Unfortunately I haven't used JBoss in Eclipse so I can't tell you which project you should be looking at, but presumably it isn't the same project where your servlets have compiled successfully.