Explanation/Reference:
* A: Stateless session beans are EJB's version of the traditional transaction processing applications, which are executed using a procedure call. The procedure executes from beginning to end and then returns the result. Once the procedure is done, nothing about the data that was manipulated or the details of the request are remembered. There is no state.
These restrictions don't mean that a stateless session bean can't have instance variables and therefore some kind of internal state. There's nothing that prevents you from keeping a variable that tracks the number of times a bean has been called or that tracks data for debugging. An instance variable can even hold a reference to a live resource like a URL connection for writing debugging data, verifying credit cards, or anything else that might be useful.