Servlet never gets destroyed

Hello.  I'm new to both Jigsaw and servlets so pardon me if this query is rather basic.  I put some trace statements inside the init() and destroy() methods of my servlet.  To my surprise, only the init() gets called everytime I invoke the servlet directly from the Address line in the browser.  And I never see destroy() getting called.  So I guess my question is, how do I explicitly unload a servlet from within JigAdmin?  If there is no way inside JigAdmin, how can I unload it then?  Would it automatically unload after some time?  Also, how come my servlet's init() always gets called (which probably means, a new instance of my servlet gets created each time)?  Maybe I do not fully understand a servlet's life-cycle.  Please someone enlighten me on this.

Thanks in advance for any help.
Ever