The Servlet API
Two packages contain the classes and interfaces that are required to build the servlets described in this chapter. These are javax.servlet and javax.servlet.http. They constitute the core of the Servlet API. Keep in mind that these packages are not part of the Java core packages. Therefore, they are not included with Java SE. Instead, they are provided by Tomcat. They are also provided by Java EE.
The Servlet API has been in a process of ongoing development and enhancement. The current servlet specification is version 3.1. However, because changes happen fast in the world of Java, you will want to check for any additions or alterations. This chapter discusses the core of the Servlet API, which will be available to most readers and works with all modern versions of the servlet specification.