In which three situations is it best to use messaging with the Service Activator? (Choose three.)
A.
when high availability is required
B.
when you want to carry data across a tier
C.
when interactive client conversations are required
D.
when subtasks can be processed in random order
E.
when you need to listen for and process messages
F.
when you need to publish messages to multiple receivers
DEF.
Reason : Use a Service Activator to receive asynchronous requests and invoke one or more business services.
For below scenario , service activator pattern would be preferable choice :
1) You want to invoke business services, POJOs, or EJB components in an asynchronous manner.
2) You want to integrate publish/subscribe and point-to-point messaging to enable asynchronous processing services.
3) You want to perform a business task that is logically composed of several business tasks.
Ref : http://www.corej2eepatterns.com/ServiceActivator.htm