Stateful vs Stateless

Question

Hello,
I am trying to understand the difference between a stateful and a stateless bean. I have read the J2EE tutorial and the whole ejb concept is great! One problem though, I don't understand what a client-bean session is or how it works. Could someone please explain this and possibly give me a qualitative example of how it fits into both the stateful and stateless bean? This should be easy duke dollars for any ejb expert! Thanks.
Chris

Answer 1

hi,
stateless session cannot maintain the state of the client i.e between the method calls no client inforamation is retained. once the request is processed the container may remove the bean from the memory or it maintain the bean in the pool in order to process the requests that are coming from other clients for the same.
eg. Assume you have a business method in bean class.
public class ConvertBean implements SessionBean
public int convertCurrency(int dollars)throws RemovteException
....code
This method is just for converting one type of currency into another type. For that we need not bother about the client. For this stateless session is sufficient.
Stateful session bean maitains the state of the client i.e it retains the information between method calls.
the object exists in the memory as long as the client is communicating with the server. Its state is not permanent.
eg . shoping cart
public class CartBean implements SessionBean
protected Vector v;
public void ejbCreate()
v = new Vector();
public void addItemToCart(Object item)
v.addElement(item);
No two clients share the same stateful session bean.