Message Driven Beans

[shawn kennedy]

If a queue of messages is sent to MDB from different components how will the MDB know from which component is which message coming

[Kyle Brown]

Unless you place some information in either the message body or the header indicating what component is sending the message, the MDB won't know. But then again, that's the point...
Kyle
P.S. What you're asking is a fundamental question about messaging architecture. I'd really recommend the book Enterprise Integration Patterns by Hohpe and Woolf, which explains how to design for messaging systems.