Loading Servlet Class : A Servlet class is loaded when first request for the servlet is received by the Web Container.
Servlet instance creation :After the Servlet class is loaded, Web Container creates the instance of it. Servlet instance is created only once in the life cycle.
Call to the init() method : init() method is called by the Web Container on servlet instance to initialize the servlet.
Signature of init() method :
public void init(ServletConfig config) throws ServletException
Call to the service() method : The containers call the service() method each time the request for servlet is received. The service() method will then call the doGet() or doPost() methos based ont eh type of the HTTP request, as explained in previous lessons.
Signature of service() method :
public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException.
Call to destroy() method: The Web Container call the destroy() method before removing servlet instance, giving it a chance for cleanup activity.
Creating a Servlet:
There are three different ways to create a servlet.
- By implementing Servlet interface.
- By extending GenericServlet class.
- By extending HttpServlet class.