Difference between GenericServlet and HttpServlet is one of
the classic Servlet
Interview Question, asked on many Servlet
and JSP Interviews on 2 to 4 years experience developers. Since both GenericServlet and HttpServlet form the basis of Servlets its important to know What are they and What is main
difference between them. From common sense and there names, its obvious that
GenericServlet is a generic and protocol-independent implementation of Servlet
interface while HttpServlet implements HTTP protocol specifics. If you are
working in Java web application or J2EE projects, you are most likely to deal
with HttpServlet all time as HTTP is main communication protocol of
web. In this Servlet JSP article we will outline some important difference between HttpServlet and
GenericServlet which is worth knowing and remembering.
GenericServlet vs HttpServlet
Here is my list of difference between HttpServlet and GenericServlet in
Java Servlet API :
1) GenericServlet provides abstract service(ServletRequest,
ServletResponse) method to implement which gets called by the container
whenever it receives request for processing, On the other hand, HttpServlet overrides
service method and provides callback on doGet(HttpServletRequest
request, HttpServletResponse) and doPost(HttpServletRequest
request, HttpServletResponse response) whenever it receives an HTTP request
from GET
or POST method. It also provides several other method based upon various
HTTP methods of sending request e.g. doPut() or doDelete() to handle
HTTP PUT and HTTP DELETE request.
2) Another difference between GenericServlet and HttpServlet is
that later is a subclass of GenericServlet and
inherit properties of GenericServlet.
3) Generic servlet provides a rather easier way to extend Servlet, its
enough to override service method to implement GenericServlet. Apart
from extending Servlet interface, it also implements ServletConfig
interface and provides way to accept initialization parameter passed to
Servlet from web.xml e.g. by using getInitParamter().
Other Servlet and JSP questions you like to prepare
though GenericServlet is protocol-independent servlet, so can we call a GenericServlet using SMTP or FTP, etc protocalls..?
ReplyDeletewhy GenericServlet is protocol-independent servlet
Deletebcz it is kind of adapter class, came to make us free from overriding all 5 methods of servlet interface while u make your own servlet class.As its name tells its a general kind of servlet and it is not specific to any protocol but HttpServlet class is http protocol specific i.e. protocol-dependent. So GenericServlet is prortocol-independent. I hope u got it.
Delete