Life Cycle Of Servlet In Java | Life Cycle Of Servlet Program In Java | Life Cycle Of Servlet In Hindi In Java

 Life Cycle of Servlet

The web container maintains the life cycle of a servlet instance. Let's see the life cycle of the servlet:

1.    Servlet class is loaded.

2.    Servlet instance is created.

3.    init method is invoked.

4.    service method is invoked.

5.    destroy method is invoked.

Fig: Life Cycle Of Servlet  

there are three states of a servlet: new, ready and end. The servlet is in new state if servlet instance is created. After invoking the init() method, Servlet comes in the ready state. In the ready state, servlet performs all the tasks. When the web container invokes the destroy() method, it shifts to the end state.

1) Servlet class is loaded

The classloader is responsible to load the servlet class. The servlet class

is loaded when the first request for the servlet is received by the web

container.

2) Servlet instance is created

The web container creates the instance of a servlet after loading the

servlet class. The servlet instance is created only once in the servlet life

cycle.

3) init method is invoked

The web container calls the init method only once after creating the  servlet instance. The init method is used to initialize the servlet. It  is the life cycle method of the javax.servlet.Servlet interface. Syntax:

            public void init(ServletConfig config) throws ServletException  

4) service method is invoked

The web container calls the service method each time when request for

 the servlet is received. If servlet is not initialized, it follows the first

three steps as described above then calls the service method. If servlet is

initialized, it calls the service method. Notice that servlet is initialized

only once.

Syntax:

    public void service(ServletRequest request, ServletResponse response)   

     throws ServletException, IOException  

5) destroy method is invoked

The web container calls the destroy method before removing the servlet

instance from the service. It gives the servlet an opportunity to clean up

any resource for example memory, thread etc.

Syntax:

          public void destroy()