Message Domains

Links

Message

Acknowledge

If the session, acknowledge mode is set to CLIENT_ACKNOWLEDGE, then call the acknowledge() method on the message to mark it as delivered.

Session session = connection.createSession(false /* not transacted */,
    Session.CLIENT_ACKNOWLEDGE);
Destination destination = JndiManager.getQueue(ctx);
MessageConsumer consumer = session.createConsumer(destination);
connection.start();
TextMessage m = (TextMessage) consumer.receive();
// Acknowledge this and all previous messages received.
m.acknowledge();

Note:

By invoking acknowledge on a consumed message, a client acknowledges all messages consumed by the session that the message was delivered to.
Calls to acknowledge are ignored for both transacted sessions and sessions specified to use implicit acknowledgement modes.

Point to Point

Queue
One to one relationship between a sender and a receiver
Many receivers can access the same queue, but only the first to pick up the message will receive it.

Session

javax.jms.Session interface

A session is a single-threaded stream of control of messages. This means that a session can not be used concurrently by two threads at the same time.

Sessions have cool properties:

Message order is guaranteed.
You can acknowledge or commit (depending on whether or not you are using transactions) several message at a time.
You can rollback or recover the messages if you need to reprocess them.

Sessions are going to be important because everything else starts from here. You create messages, producers, consumers, destinations from the Session.