Shortly before this book went to print, Sun Microsystems published the Proposed Final Draft of the Servlet API 2.3 specification.
This is not the specification’s final form; the Proposed Final Draft is one step away from a formal Final Release and technical details are still subject to change. However, those changes should not be significant—in fact, server vendors have already begun to implement the new features. In this chapter, I will review in detail everything that changed between API 2.2 and API 2.3. I will also explain the reasons for the changes and demonstrate how to write servlets using the new features.
Servlet API 2.3 actually leaves the core of servlets relatively untouched, which indicates that servlets have reached a high level of maturity. Most of the action has involved adding new features outside the core. Among the changes:
Servlets now require JDK 1.2 or later.
A filter mechanism has (finally) been created.
Application lifecycle events have been added.
New internationalization support has been added.
The technique to express inter-JAR dependencies has been formalized.
Rules for class loading have been clarified.
New error and security attributes have been added.
HttpUtils class has been deprecated.
Various new helpful methods have been added.
Several DTD behaviors have been expanded and clarified.
Other clarifications have been made, but they mostly concern server vendors, not general ...