What are the life-cycle methods in JSP?

A JSP page services requests as a servlet. Thus, the life cycle and many of the capabilities of JSP pages (in particular the dynamic aspects) are determined by Java Servlet technology. The life-cycle methods of the JSP are:

• jspInit(): The container calls the jspInit() to initialize the servlet instance. It is called before any other method, and is called only once for a servlet instance.
• _jspService(): The container calls the _jspService() for each request and it passes the request and the response objects. _jspService() method cann?t be overridden.
• jspDestroy(): The container calls this when its instance is about to destroyed.

The jspInit() and jspDestroy() methods can be overridden within a JSP page.

These methods are generated after JSP page translated and compiled, the JSP pages's servlet follows the servlet life-cycle:

• If an instance of the JSP page's servlet does not exist, the container
  • Loads the JSP page's servlet class
  • Instantiates an instance of the servlet class
  • Initializes the servlet instance by calling the jspInit method
• The container invokes the _jspService method, passing request and response objects.

If the container needs to remove the JSP page's servlet, it calls the jspDestroy method.

Printer-friendly version | Mail this to a friend