I have just completed to write a short guide for learning JSP. You can find it for free personal and academic usage at http://www.zindell.com/IsraeliJSPBook/ch1.htm. I hope it will assist you with doing your first steps. Make sure you set the right encoding (Hebrew Windows).
The Visitor Design Pattern
The visitor design pattern allows us to add operations to objects that already exist without modifying their classes and without extending them.