difference between GenericServlet and HttpServlet

javax.servlet.GenericServletSignature: public abstract class GenericServlet extends java.lang.Object implements Servlet, ServletConfig, java.io.Serializable

• GenericServlet defines a generic, protocol-independent servlet.
• GenericServlet gives a blueprint and makes writing servlet easier.
• GenericServlet provides simple versions of the lifecycle methods init and destroy and of the methods in the ServletConfig interface.
• GenericServlet implements the log method, declared in the ServletContext interface.
• To write a generic servlet, it is sufficient to override the abstract service method.

javax.servlet.http.HttpServlet
Signature: public abstract class HttpServlet extends GenericServlet implements java.io.Serializable

• HttpServlet defines a HTTP protocol specific servlet.
• HttpServlet gives a blueprint for Http servlet and makes writing them easier.
• HttpServlet extends the GenericServlet and hence inherits the properties GenericServlet.