⟩ A client invokes a method on a stateful session bean instance deployed in the WebLogic Server. While the method execution is in progress another method call arrives on the server. What will be the result?
a. RemoteException is thrown if the value of concurrency-strategy property is false
b. EJBException is thrown if the value of concurrency-strategy property is false
c. The EJB container blocks the concurrent method call and allows it to proceed when the previous call has completed if the value of allow-concurrent-calls is true
d. In all cases, RemoteException is thrown
Choice C is correct. By default, simultaneous access to a stateful session EJB results in a RemoteException. However, you can set the allow-concurrent-calls option in the WebLogic EJB deployment descriptor to specify that a stateful session bean instance will allow concurrent method calls. This access restriction on stateful session EJBs applies whether the EJB client is remote or internal to WebLogic Server. By default, allows-concurrent-calls is false. However, when this value is set to true, the EJB container blocks the concurrent method call and allows it to proceed when the previous call has completed.
The concurrency-strategy element determines ejbLoad() and ejbStore() behavior for entity EJB instances.
