I am reading about EJB Session Bean. I have worked mostly on spring and on website we keep the session in normal session object. Documents of session bean says that if i have a shopping cart, i use session bean? is that mean i don’t need to take care of session on JSP level? and can this session bean also be used to maintain the user session.
I don’t agree what i write last in above paragraph. Isn’t it repetition of code and extra use of memory.
Please explain this concept which i am not getting at all.
A session in a Servlet, is maintained by the Servlet Container through the HttpSession object, that is acquired through the request object. You cannot really instantiate a new HttpSession object, and it doesn’t contains any business logic, but is more of a place where to store objects.
A session in EJB is maintained using the SessionBeans. You design beans that can contain business logic, and that can be used by the clients. You have two different session beans: Stateful and Stateless. The first one is somehow connected with a single client. It maintains the state for that client, can be used only by that client and when the client “dies” then the session bean is “lost”.
A Stateless Session Bean doesn’t maintain any state and there is no guarantee that the same client will use the same stateless bean, even for two calls one after the other. The lifecycle of a Stateless Session EJB is slightly different from the one of a Stateful Session EJB. Is EJB Container’s responsability to take care of knowing exactly how to track each session and redirect the request from a client to the correct instance of a Session Bean. The way this is done is vendor dependant, and is part of the contract.