JMS: The difference between Message Acknowledgement and Transacted Session

Message Acknowledgement or Transacted Session?

Posted on 05/30/2011 ,
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JMS is one of the oldest Java EE specifications (JMS 1.0 specification is dated 11/1999), however, questions about
the difference between message acknowledgement and transacted session still come up. The difference is especially subtle when programmatic client acknowledgement (

Session.CLIENT_ACKNOWLEDGE

) is used since

Message.acknowledge()

and

Session.recover()

are similar to

Session.commit()

and

Session.rollback()

. So how are these
APIs different?

The bottom line is that there is no difference if you deal only with a single resource (Queue or Topic) within a session. If all you do is consuming messages from a single queue, it does not matter whether you use acknowledgements or transacted sessions
(although in my opinion it is more intuitive to use Session.commit/rollback).

Session.commit()

invokes

Message.acknowledge()

under the covers and

Session.rollback()

invokes

recover()

.

However, if you're dealing with multiple JMS resources withing the same session (or multiple consumers/producers), the transacted session mechanism is what you want to use. For example, you may consume messages from one queue and
then put messages on a different queue using the same JMS
session. The transacted session will treat all consumed and produced messages as part of a single transaction and will commit or rollback all messages at once. Message acknowledgement on a non-transacted session will "commit" consumed messages independently
of the produced ones.

Transacted sessions are limited to JMS resources; container-managed transactions and
JTA is required to managed JMS
and non-JMS resources (e.g., getting a message from a queue and updating a database).

As a summary, the different mechanisms discussed here differ in terms of the types of resources managed as part of transactions:

Message acknowledgement: messages consumed from a single destination.
Transacted session: multiple JMS resources within the same
JMS session.
Container-managed transactions: multiple JMS and non-JMS resources.

For a more in-depth discussion of different transaction mechanisms, refer to
this article.

From: http://myarch.com/message-acknowledgement-or-transacted-session