As per JSP/Servlet API doc, HttpServlet provides an abstract class to be subclassed to create an HTTP servlet suitable for a Web site. A subclass of HttpServlet must override at least one method, usually one of these:

  1. doGet, if the servlet supports HTTP GET requests
  2. doPost, for HTTP POST requests
  3. doPut, for HTTP PUT requests
  4. doDelete, for HTTP DELETE requests
  5. init and destroy, to manage resources that are held for the life of the servlet
  6. getServletInfo, which the servlet uses to provide information about itself

HttpServlet Class Detail :-