Management of Bean Instance Lifecycle

To effectively utilize system resources, EJB servers manage the lifecycle of the bean instances contained in the container.

• The EJB spec defines how the container has to manage the lifecycle of each kind of enterprise beans.
• The interfaces through which the container notifies a bean about significant events in it's lifecycle are also defined. The bean thus may receive
  • notification before passivation (deactivation) of the bean
  • notification after reactivation of the bean
  • request to store/reload the bean's internal state
  • notification before removal of the bean instance

Note: the actual instant of creation, passivation and activation of bean instances are dependent on container internal resource management policy. However, bean instance lifecycle management is completely hidden from the client. If the bean instance was passivated when the client invokes a request to the bean, it is activated automatically.

For stateless session bean, a pool of equivalent instance exists and the container may assign arbitrary instance to process the client request.