Answer
Between the client and the session bean, the state of the conversation can be
maintained using a stateful session bean. The instance variables contain a
state only during the invocation by a client method.
It implements ‘javax.ejb.SessionBean’ interface and is deployed with the
declarative attribute ‘stateful’.
They have instance fields that can be initialized and modified by the client
with each method invocation. The bean can use the conversational states as its
business process methods.