Hi, Yesterday I was taking one of the mock exams in Whizlabs simulator and there were questions about how EJB supports Synchronous (not asynchronous) messaging. What do they mean by Synchronous messaging? Do they just mean the RMI call which is Synchronous? Or do they mean reading a Queue directly? The question was very confusing.
Asynchronous messaging is supported by message-driven beans, but JMS also has a request/paradigm that can be utilized by any bean through the JMS API. A bean can use the JMS API to send a message and wait for the synchronous reply. Check out section 2.10 'Request/Reply' in the JMS 1.1 spec
SCJP, SCWCD, SCBCD, SCEA 5
J J Wright
Joined: Jul 02, 2008
They could of course also be referring to some kind of synchronous RPC style web service. Remember that both web services and JMS can be used in an synchronous or asynchronous fashion.