Advanced java programming

Life cycle of Servlet

M.Jeevana sujitha

Assistant Professor

​

Department of Computer Science and Engineering

SRKR Engineering College, Bhimavaram, A.P. - 534204

OBJECTIVES

The Objective of this lecture is

• To learn about life cycle of servlet.

Life cycle of Servlet

Life cycle of Servlet

• There are 3 important methods in servlet life cycle. They are
• init()
• service()
• destroy()

Life cycle of Servlet

init(): The init() method is designed to be called only once in the life cycle of servlet.

• It is called when the servlet is first created.
• It is used for one-time initializations.
• The servlet is normally created when a user first invokes a URL corresponding to the servlet.

Syntax:

public void init() throws ServletException

{

Initialization code

}

Life cycle of Servlet

service(): The service () method is the main method to

perform the actual task.

• The servlet container calls the service() method to handle

requests coming from the client and to write the

formatted response back to the client.

• Each time the server receives a request for a servlet, the

server creates a new thread and calls the service()

method.

• The service method checks the Http request type(GET or

POST) and calls doGet() or doPost() methods.

Syntax:

public void service(ServletRequest req, ServletResponse res)

{

Actual business logic for providing service to client

}

Life cycle of Servlet

destroy(): The destroy() method is called only once at the end of the life cycle of servlet.

• It gives our servlet a chance to close database connections and perform other cleanup activities.
• After the destroy() method is called, the servlet object is marked for garbage collection.

Syntax:

public void destroy()

{

Closing database connections

}

THANK YOU