Head First Servlets and JSP, 2nd Edition

Lifecycle of a JSP

You write the .jsp file.

The Container writes the .java file for the servlet your JSP becomes.

1. Kim writes a .jsp file, and deploys it as part of a web app.

   The Container “reads” the web.xml (DD) for this app, but doesn’t do anything else with the .jsp file (until the first time it’s requested).

   

2. The client hits a link that asks for the .jsp.

   The Container tries to TRANSLATE the .jsp into .java source code for a servlet class.

   Note

   JSP syntax errors are caught in this phase.

   

3. The Container tries to COMPILE the servlet .java source into a .class file.

   

4. The Container LOADS the newly-generated servlet class.

   

5. The Container instantiates the servlet and causes the servlet’s jspInit() method to run.

   The object is now a full-fledged servlet, ready to accept client requests.

   

6. The Container creates a new thread to handle this client’s request, and the servlet’s _jspService() method runs.

   

   Everything ...