Do the JMS spec or the various implementations sup

Question

Lets say Producer sends a message to the JMS Topic "news". Consumer1 reads the message, but Consumer2 is offline so he hasn't read the message yet.

Is there any build-in (to the spec or impl) way for the Producer to be notified that Consumer1 has read his message, but Consumer2 has not? This would, in fact, mirror the Read Notification of an email.

Clearly you could implement this by having each Consumer send an acknowledgement, but I'm looking for something already a part of JMS or a JMS system.

Answer 1

The JMS FAQ says

JMS API messaging provides guaranteed delivery via the once-and-only-once delivery semantics of PERSISTENT messages. In addition, message consumers can insure reliable processing of messages by using either CLIENT_ACKNOWLEDGE mode or transacted sessions. This achieves reliable delivery with minimum synchronization and is the enterprise messaging model most vendors and developers prefer.

The JMS API does not define a schema of systems messages (such as delivery notifications). If an application requires acknowledgment of message receipt, it can define an application-level acknowledgment message.

These issues are more clearly understood when they are examined in the context of publish/subscribe applications. In this context, synchronous delivery and/or system acknowledgment of receipt are not an effective mechanism for implementing reliable applications (because producers by definition are not, and do not want to be, responsible for end-to-end message delivery).

I'm no expert, but I think this is saying that the spec doesn't define a way for a consumer to confirm receipt to a producer, by design. I don't know of any implementations that do - and if they did, it looks like it'd be a big departure from the model the spec captures.