Defines a generic, protocol-independent
servlet. To write an HTTP servlet for use on the Web, extend HttpServlet instead.
GenericServlet implements the Servlet and ServletConfig interfaces.
GenericServlet may be directly extended by a servlet, although it's more common to extend a protocol-specific subclass such as HttpServlet.
GenericServlet makes writing servlets easier. It provides simple versions of the lifecycle methods init and destroy and of the methods in the ServletConfig interface.
GenericServlet also implements the log method, declared in the ServletContext interface.
To write a generic servlet, you need only override the abstract service method.
ServletsFaq