Talk:JavaServer Pages compiler

does the jsp compiler, compile a jsp page for every change made...if so how does it detect that a change is made...... for eg: u open a jsp page and view it...go to the real source and make some static changes or even script changes...and then u press refresh, still while the server is running....u can view the changes made!!! so where, when and how does the server know that the change is made and when is it processed?????