Message-driven beans, activation specifications, and listener ports

Guidelines, related to versions of WebSphere® Application Server, to help you choose when to configure your message-driven beans to work with listener ports rather than activation specifications.

You can configure the following resources for message-driven beans:
  • Activation specifications for message-driven beans that comply with Java™ EE Connector Architecture (JCA) Version 1.5 and later.
  • The message listener service, listener ports, and listeners for any message-driven beans that you want to deploy against listener ports.

Activation specifications are the standardized way to manage and configure the relationship between an MDB running in WebSphere Application Server and a destination in WebSphere MQ. They combine the configuration of connectivity, the Java Message Service (JMS) destination and the runtime characteristics of the MDB, within a single object.

Activation specifications supersede the use of listener ports, which became a stabilized feature in WebSphere Application Server Version 7.0. There are several advantages to using activation specifications over listener ports:
  • Activation specifications are simple to configure, because they only require two objects: the activation specification and a message destination. Listener ports require three objects: a connection factory, a message destination, and the message listener port itself.
  • Activation specifications are not limited to the server scope. They can be defined at any administrative scope in WebSphere Application Server. Message listener ports must be configured at the server scope. This means that each server in a node requires its own listener port. For example, if a node is made up of three servers, three separate listener ports must be configured. Activation specifications can be configured at the node scope, so in the example only one activation specification would be needed.
  • Activation specifications are part of the Java Platform, Enterprise Edition Connector Architecture 1.5 and 1.6 standards specification (JCA 1.5 and 1.6). Listener port support in WebSphere Application Server makes use of the application server facilities interfaces defined in the JMS specification, but is not part of any specification itself.

For WebSphere Application Server Version 7 and later, listener ports are stabilized. For more information, read the topic about stabilized features. Plan to migrate your WebSphere MQ message-driven bean deployment configurations from using listener ports to using activation specifications. However, you should not begin this migration until you are sure the application does not have to work on application servers earlier than WebSphere Application Server Version 7. For example, if you have an application server cluster with some members at Version 6.1 and some at a later version, you should not migrate applications on that cluster to use activation specifications until after you migrate all the application servers in the cluster to the later version. [z/OS]Also, when you migrate to activation specifications on the z/OS® platform, you must enable the Control Region Adjunct (CRA) process of the application server (either by selecting Enable JCA based inbound message delivery on the JMS provider settings panel, or by using the manageWMQ command to include starting the CRA process as part of starting an application server).

If you want to use message-driven beans with a messaging provider that does not have a JCA Version 1.5 or 1.6 resource adapter, you cannot use activation specifications and therefore you must configure your beans against a listener port. There are also a few scenarios in which, although you could use activation specifications, you might still choose to use listener ports. For example, for compatibility with existing message-driven bean applications. Here are some guidelines, related to versions of WebSphere Application Server, to help you choose when to use listener ports rather than activation specifications:

  • WebSphere Application Server Version 4 does not support message-driven beans, so listener ports and activation specifications are not applicable. WebSphere Application Server Version 4 does support message beans, but these are not message-driven beans.
  • WebSphere Application Server Version 5 supports EJB 2.0 (JMS only) message-driven beans that are deployed using listener ports. This deployment technology is sometimes called application server facility (ASF).
  • WebSphere Application Server Version 6 continues to support message-driven beans that are deployed to use listener ports, and also supports JCA, which you can use to deploy message-driven beans that use activation specifications. This gives you the following options for deploying message-driven beans on WebSphere Application Server Version 6:
    • You must deploy default messaging (service integration bus) message-driven beans to use activation specifications.
    • You must deploy WebSphere MQ message-driven beans to use listener ports.
    • You can deploy third-party messaging message-driven beans to use either listener ports or activation specifications, depending on the facilities available from your third-party messaging provider.
  • WebSphere Application Server Version 7.0 or later continues to support the same options for message-driven bean deployment that WebSphere Application Server Version 6 supports, and adds a new option for WebSphere MQ message-driven beans. This gives you the following options for deploying message-driven beans on Version 7.0 or later:
    • You must deploy default messaging (service integration bus) message-driven beans to use activation specifications.
    • You can deploy new and existing WebSphere MQ message-driven beans to use listener ports (as on WebSphere Application Server Version 6) or to use activation specifications.
    • You can deploy third-party messaging message-driven beans to use either listener ports or activation specifications, depending on the facilities available from your third-party messaging provider.

To assist in migrating listener ports to activation specifications, the WebSphere Application Server administrative console provides a Convert listener port to activation specification wizard on the Message listener port collection panel. This allows you to convert existing listener ports into activation specifications. However, this function only creates a new activation specification with the same configuration used by the listener port. It does not modify application deployments to use the newly created activation specification.