Recently i have been assigned to an application which is built on Servlets/Jsp's, and i have been given some assignment, to implement that change i need to study the complete existing flow of the application then only i can implement the requested change, can you people suggest what are the ways in which we can understand the application flow built in Java (Servlets/Jsps) in detail and work on the given new change.
If you are new to any application and you want to know the flow of application the best way to understand using Debugging.
You application totally build on Jsp and servlet. So all mapping of your application at your web.xml file if they follow MVC. So, just check your url pattern with your servlet mapping and check which servlet is responsible for request. Just note down and put breck point at that servlet and check all variable value also. Now you get idea about your application.
I was thinking debugging is most and best way way to solve any problem and understand flow of application.
If you want to learn about debugging i think this link will help you more.....
IMO there aren't any really *good* ways to break down high-level app flow in apps like this.
If you want to document app flow within the Java code itself there are many ways to go about getting it, from debugging as suggested (thorough, but neither automatic nor practical for large apps) to detailed logging with post-processing to create sequence diagrams etc.