how to remove this error

[ravinder64]

lifecycle is not abstract and does not override abstract method service(javax.servlet.servletrequest req,javax.servletresponse rs)in javax.servlet.genericservlet

[masijade]

You've written a class that extends "GenericServlet" (which contains the abstract method "service(request, response)") which you either have to implement or declare your class abstract (which is exactly what the exception says).

But, if you are writing a simple web service, you shouldn't be extending GenericServlet anyway. You should be extending HttpServlet.