Improving the performance of a JSP application should use the same approach as improving the performance of any application.
1. Start by measuring the performance, in detail, to find out which parts of the process take longest. Addresss them first, when you have speeded up the slowest so that it is no longer the slowest, move on to the next slowest and improve that.
2. Keep an open mind. If the slowest part is the database (say), then optimize that, or if your webserver/JSP container is slow, consider reconfiguring/replacing that.
3. If the slowness is actually in the
Java, apply the usual java speedups: make sure your code is doing only what it really needs to, re-use objects wherever possible rather than calling 'new' (especially very slow things like database connections or query results) and so on.
Above all, find out what is slow before you start "optimizing", It will probably surprise you! If the problem is in the Java, consider asking some more detailed questions in the "performance" forum we have set up for just that purpose or consider buying
Java Performance Tuning by Jack Shirazi.