Hey, I'm sort of new to this, so this may be stupid, or obvious, but you say you need to use it in other JSP pages. I think that means you need to consider the scope, and I think if you put it in request scope and then the browser requests another page, you will not be able to access it.
I believe that using hidden fields to maintain state is a bad idea. It puts a big security hole in your application.
In my previous work place, we contracted a testing company to do some security vulnerablity testing for us. The tester put our application in an unexpected state just by fiddling with the hidden fields. We then spent couple of weeks removing all hidden fields from our JSP forms.
MCSD, SCJP, SCWCD, SCBCD, SCJD (in progress - URLybird 1.2.1)