Sun Java System Message Queue 4.3 Developer's Guide for Java Clients

Acknowledgment Mode

Other than using transactions, you can ensure reliable delivery by having the client acknowledge receiving a message. If a session is closed without the client acknowledging the message or if the message broker fails before the acknowledgment is processed, the broker redelivers that message, setting a JMSRedelivered flag.

For a non-transacted session, the client can choose one of three acknowledgment modes, each of which has its own performance characteristics:

Performance is impacted by acknowledgment mode for the following reasons: