Peter,
You have to get your client/server model in your head straight. With JSP's you are talking about an "WEB-application". This means the application is running on a remote server (or local), and is accessed through a web browser on a client PC. Of course the running and configuration cannot be influenced from the client (but from using servlets on the server that have been designed to do so by the software dleiverer of the server (to make life easier), these are usually protected by passwords, so that not everybody can change the configuration of YOUR webserver and application server).
Unloading servlets is done by the AS (application server), when the AS is stopped or re-started.
If you want to make users "leave" the application. Re-root them to the home page set in the browser and clear the complete history in a javascript function (client side programming).
regards,
Jeroen.