JavaServer Faces (JSF) applications are servlet / JavaServer Pages (JSP) applications based on the Model 2 architecture. Therefore, writing JSF applications requires you to be familiar with the servlet and JSP technologies, as well as the related technologies of JavaBeans and custom tags, plus the Model 2 architecture. This book assumes that you already have some servlet/JSP programming experience. However, to quickly refresh your memory, this chapter presents a brief overview of those technologies, focusing on topics directly related to writing JSF applications.

Servlets

Servlets are Java classes that run on a special Web server called a servlet/JSP container or Web container. In servlet programming, you use the classes and interfaces from two packages:

• javax.servlet, which contains basic types for servlet programming
• javax.servlet.http, which contains interfaces and classes that extend those from the javax.servlet package

The most important type in these two packages is the javax.servlet.Servlet interface, which all servlets must implement (or extend a class that does). We’ll begin our review of servlets by taking a look at the Servlet interface.

Using the Servlet Interface

The javax.servlet.Servlet interface defines the three lifecycle methods: init, service, and destroy. The servlet container calls these methods during the life of a servlet.

NOTE: The alternative to implementing the Servlet interface directly is to extend the javax.servlet.GenericServlet class or the javax.servlet.http.HttpServlet class.

Remember: This is part one of the first chapter of JavaServer Faces Programming, by Budi Kurniawan (McGraw-Hill/Osborne, ISBN 0-07-222983). Stay tuned for part 2 of "Overviews of Java Web Technologies," where we learn about JSP, JavaBeans, and Model 2.  Buy this book!