Jothi, A couple years ago I was curious and set my debugger to the line of PortableRemoteObject.narrow() in my code and looked at the fields in the object. I saw a bunch of networking related stuff. I don't recall exactly what is in there anymore so it's hard to elaborate. You could try the same experiment if you are really curious.
Jeanne, thanks for the hint. I just want to ask you one more thing is that did you ever come across a line that talks about this in the Head First EJB? If yes could you please tell me which page is that?