The idea behind messaging is to send messages, essentially units of data, from one process to another. Messages can be about events that have taken place, requests for data, or replies to queries.
Message-driven beans are J2EE components that have been designed to be asynchronous message consumers. In other words, another J2EE entity, such as a session bean, can simply send a message on to the message-driven bean, and then go on about its business while the message-driven bean figures out how to process the message it has received.
The messaging paradigm offers various advantages over the conventional synchronous operation invocation paradigm.
For instance, it can be used as a relatively simple solution for ...