are you in a kind of hurry ?
you cannot get the screen size just by jsp since this is client side (as already mentioned in the post above).
but try this:
on first page (eg. index.html) , read the screensize with JavaScript, forward to the second page with the screensize as parameters in the url. the second page reads the parameters (the second page would be a
servlet or a jsp) and stores it somewhere (session, db...).
karl