The JMS Provider

The Application Server support for JMS messaging, in general, and for message-driven beans, in particular, requires messaging middleware that implements the JMS specification: a JMS provider. The Application Server uses the Sun Java System Message Queue software as its native JMS provider. The Message Queue software is tightly integrated into theApplication Server, providing transparent JMS messaging support. This support is known within Application Server as the JMS Service. The JMS Service requires only minimal administration.

The relationship of the Message Queue software to the Application Server can be one of these types: EMBEDDED, LOCAL, or REMOTE. The effects of these choices on the Message Queue broker life cycle are as follows:

• If the type is EMBEDDED, the Application Server and Message Queue software run in the same JVM, and the networking stack is bypassed. The Message Queue broker is started and stopped automatically by the Application Server. This is the default for the Domain Administration Server (DAS).

  Lazy initialization starts the default embedded broker on the first access of JMS services rather than at Application Server startup. EMBEDDED mode is not a supported configuration for a cluster.

• If the type is LOCAL, the Message Queue broker starts when the Application Server starts. This is the default for all Application Server instances except the DAS.

  The LOCAL setting implicitly sets up a 1:1 relationship between an Application Server instance and a Message Queue broker. When you create an Application Server cluster, a Message Queue cluster is automatically created as well. During cluster creation, each instance in the Application Server cluster is automatically configured with a broker in the Message Queue cluster, and a unique broker port is determined.

  The first Application Server instance's Message Queue broker is set as the master broker. If you delete the first Application Server instance, you must use Message Queue administration tools to migrate the master broker. For details, see Managing the Configuration Change Record in Sun Java System Message Queue 4.1 Administration Guide. However, if HADB is installed, there is no master broker. For more information about HADB, see JMS Service High Availability.

• If the type is REMOTE, the Message Queue broker must be started separately. For information about starting the broker, see the Sun Java System Message Queue 4.1 Administration Guide.

For more information about setting the type and the default JMS host, see Configuring the JMS Service.

For more information about the Message Queue software, refer to the documentation at http://docs.sun.com/coll/1343.4.

For general information about the JMS API, see the JMS web page at http://java.sun.com/products/jms/index.html.

Some topics in the documentation pertain to features that are available only in domains that are configured to support clusters. Examples of domains that support clusters are domains that are created with the cluster profile or the enterprise profile. For information about profiles, see Usage Profiles in Sun Java System Application Server 9.1 Administration Guide.