Session Beans - II
Because of scalability reasons, container keeps some objects as active while passivating some of them. The passivation process takes place if the bean is not in a transaction. To help the container’s management of resources, EJB specifies two kinds of session beans: stateless and stateful.
Stateless session beans contain no conversational state and any bean instance can be used for any client invocation since there is no state information between method calls.
Stateful session bean contains conversational state across method invocations and transactions.
A state of a conversational bean is defined by its field values and transitive closure of the objects from the session bean’s fields by following the object references.