Java™ Message Service (JMS) basics

In the JMS model, message-based communication between producing and consuming applications is coordinated by an intermediate component known as a message broker that acts as the clearinghouse for message exchange. The message broker provides a registry of the available destinations to which messages can be posted, and a store for messages that have been posted but not yet consumed.

Applications acting in the role of message producer create messages and post them (through the broker) to the destination appropriate for the type of message. The messages are associated with the destination and retained by the broker until they have been consumed by interested applications.

Applications acting in the role of message consumer connect to a message destination (again, through the broker) in order to express interest in receiving messages posted to it. As messages are posted to the destination by producers, the broker makes the messages available to interested consumers which then receive and process the message.

In the Web Services API notification facility, the HMC acts both as the message broker and the message producer for API notification messages. API client applications act as message consumers.

For the broker function, the HMC includes an integrated JMS message broker implementation based on Apache ActiveMQ, an open, standards-based implementation of JMS. This integrated broker is configured to allow internal HMC function to act as message producers, and to allow external applications to connect as message consumers. However, external applications cannot produce and send messages using the HMC integrated broker.