___________________________________________________________________________ in stateful session beans non-transient and non-serializable fields have to be set to null before passivation.
if this statement is true then what happens if we wont set them to null? ___________________________________________________________________________
The conversational state of stateful session bean is defined as the session bean instance's field values, plus the transitive closure of the objects from the instance's fileds reached by following Java object references.
In advanced cases, a session bean's conversational state may contain open resources, such as open sockets, and open database cursors.
A CONTAINER CAN NOT RETAIN SUCH RESOURCES WHEN A SESSION BEAN INSTANCE IS PASSIVATED.
A developer of such a session bean must close and open the resources in the ejbPassivate and ejbActivate notifications.