an applet is a client side program, basically the JAVA equivalent of a javascript. If you aren't trying to keep the code secret or do anything secure, then an applet's cool for whatever.
a servlet is a serverside program, I'd avoid using them in favor of JSPs which compile into SERVLETS and are then run on the server.
Facelets are basically an extention of JSP. Which turns into servlets.
Servlets use a bunch of
println("<html>");
println("<head>");
and so on, which isn't cool, because you have to type println like a billion times. JSP and JSF translate pages with special tags in them to basically assume everything NOT in the special tags is just HTML, because the page mostly will be HTML.
