The Servlet API
Two packages contain the code the it servlet: javax.servlet and javax.servlet.http. They constitute the Servlet API.It the time of this writing) these packages are not part of the java : Therefore, they arc nut included in the Java Development Kit ODK). You must download the Java Servlet Development Kit OSDK) to obtain their functionality.The Servlet API is supported by most Web servers, such as those from Sun Microsoit, and others. Check the Sun Microsystems Web pages at http://java.sun.co for additional information.
The javax.servlet Package
The javax.servlet package contains a number of interfaces and classes that establish the framework in which services operate. The following table summarizes the interfaces that arc provided in this package The most significant of these is Servlet, All servlets must implement this interface or extend a class that implements the interface. The ServletRequest and Servletresponse interfaces arc also very important.