The J2EE 1.4 Standard
Here are the significant changes incorporated in the J2EE1.4 specification when compared to the previous technology.
Java Servlet 2.4
The Java Servlet 2.4 represents a relatively small upgrade with small enhancements and clarifications to the prior version 2.3. Here are the changes:
The deployment descriptor for the servlet 2.4 now uses the XML schema instead of the DTD.
New attributes are added in the RequestDispatcher for the forward method.
SingleThreadModel interface is deprecated.
New methods are added to the ServletRequest interface and the ServletRequestWrapper.
The HttpSession.logout method is removed.
Servlets now require HTTP/1.1 and J2SE (Java 2 Platform, Standard Edition) 1.3 or higher and can work with J2EE 1.4. ...