Servlets run on the server. The only way to invoke them is via a round-trip to
the server. You can make this more convenient for the user with Javascript
(AJAX) to handle the request and response under the hood.

There are tricks for dividing a page into independently updated parts, but
they are not really needed unless you have a very thick page and a very slow
connection. If you can design your page to be rather lean, then just go ahead
and reload the entire page.

Sometimes you phrase a question to yourself in terms of a particular strategy,
"How can I avoid a page reload?", which limits your options and blinds you to
costs. (Segmenting a page is more complex than showing a "normal" HTML page.)
It is useful to step back and ask yourself the question in terms of a goal,
"How can I make a smooth user experience?" Note that the first question is
computer-centric, the second human-centric.

- Lew

hi
i think if you do same programme in JSP and in jsp page you utilize
action listener and in  listener   will act after user will going to
select your first option.and by threading your programme will going to
other option to user.