When you migrate from WebSphere® Application Server Version 5 embedded messaging to the default messaging provider, you do not have to change Version 5.1 JMS applications, JMS resource definitions, or client JMS resource definitions. Use of bus resources is enabled by a WebSphere MQ client link, and the wildcard syntax is converted automatically for interoperation between Version 5.1 and later versions.
When migrating a WebSphere Application Server Version 5.1 node to later versions, you do not need to make any changes to JMS applications; they can continue to use their same deployment and installation, and their same configurations of Version 5.1 JMS resources (with one exception given in You do not have to change Version 5.1 JMS resource definitions).
The applications can continue to use the same JMS API classes and listener ports, but rather than communicating with a WebSphere MQ queue manager, the applications communicate with a messaging engine on a service integration bus.
When migrating a WebSphere Application Server Version 5.1 node to later versions, you do not need to make any changes to JMS resource definitions. JMS applications can continue to use their same configurations of Version 5.1 JMS resources, with the following exception.
The exception to this is for JMS applications that use the Version 5 embedded messaging provider DIRECT port for publish/subscribe messaging, as set on the WebSphere Application Server topic connection factory. If any WebSphere Application Server Version 5.1 topic connection factory has the Port property set to DIRECT, change it to QUEUED before use with the default messaging provider in the later version.
If a node is migrated to a later version, the JMS resources are not changed, except to use the new naming convention. That is, the administrative name for the Version 5 embedded messaging JMS resources is changed from WebSphere JMS Provider resources to V5 Default Messaging resources.
Listener ports are copied over unmodified from the Version 5.1 configuration, and are used on the later version whenever the associated Version 5 default messaging resources are used.
After migration to the later version, the JMS resources are implemented through the default messaging provider. You can use the administrative console to manage the JMS resources as Version 5.1 default messaging JMS resources. For example, in the administrative console you can list Version 5.1 default messaging JMS queue connection factories by clicking
You should replace Version 5.1 default messaging JMS resources with equivalent default messaging provider JMS resources as soon as is conveniently possible (after all JMS applications that use those resources have been moved onto the later version). This enables you to benefit from the better performance of the default messaging provider, and to exploit the use of multiple messaging engines in a service integration bus, and other default messaging functions enabled by service integration technologies.
You can replace JMS resources manually, for example by using the WebSphere Application Server administrative console. Alternatively, you can replace the resources programmatically, for example by some scripting that retrieves the Version 5.1 property values then creates JMS resources for the later version, with values appropriate to that environment and your use of the Version 5.1 properties.
New JMS resources should be created as JMS resources in the later version. Any wsadmin or JMX scripts that create Version 5.1 JMS resources must be changed to create JMS resources for use in the later version.
JMS client applications that have JMS resources configured by using the Application Client Resource Configuration Tool (ACRCT) in WebSphere Application Server Version 5.1 should continue to work without change with later versions.
You should replace Version 5.1 default messaging JMS resources with equivalent default messaging provider JMS resources as soon as is conveniently possible (after all the application servers have been migrated onto the later version). You should use the ACRCT ofo the later version to replace the JMS resources and to create any new JMS resources. New JMS resources should be created as JMS resources for the later version.
When migrating a WebSphere Application Server Version 5.1 node to a later version, any messages (and knowledge of durable subscriptions) held by the JMS server are not migrated automatically. Whether you have to drain all the JMS queues depends upon your migration strategy.
For each JMS queue defined on the JMS server, the migration process automatically creates a new bus queue with the same name as the Version 5.1 JMS queue, and creates a message point assigned to the messaging engine. Messages sent to the JMS queues are stored and processed at the message point.
A JMS application that uses a message-driven bean and its listener port in WebSphere Application Server Version 5.1 can continue to use the listener port without change in later versions. However, the message listener service uses the Application Server Facilities (ASF), which are an optional part of the JMS specification. Also, ASF is not supported by the service integration technologies on which the later default messaging provider is implemented.
The default messaging provider in later versions is implemented as a Java™ Platform, Enterprise Edition (Java EE) Connector Architecture (JCA) resource adapter, for which inbound connectivity is configured as an activation specification. Therefore, as soon as is conveniently possible, you should replace any listener port with a JMS activation specification for use by MDB applications with the default messaging provider.
If you used the listener port retry count in WebSphere Application Server Version 5.1, there is one extra consideration. The Java EE Connection Architecture has no concept of a listener port retry count, so this is not supported by the later default messaging provider. This should not present a problem because the default messaging provides destinations with a "Maximum failed deliveries" setting. This defines the maximum number of times that the service tries to deliver a message to the destination before forwarding it to the exception destination. Although applications do not have to be changed, any wsadmin or JMX scripts that make use of the listener port retry count must be changed to make use of the "Maximum failed deliveries" setting for use in the later version.
Version 5 embedded messaging uses WebSphere MQ technology, and for communication uses WebSphere MQ client protocols. The default messaging provider in later versions uses fully-integrated Java technology, and JMS applications access JMS resources through the messaging engines on a service integration bus.
JMS applications developed for WebSphere Application Server Version 5.1 can use resources on a service integration bus through a WebSphere MQ client link assigned to a messaging engine on the service integration bus. The WebSphere MQ client link is provided only for use with JMS applications developed for WebSphere Application Server Version 5.1. This link presents itself as a queue manager and transforms between the WebSphere MQ client protocols used by JMS applications developed for WebSphere Application Server Version 5.1 and the protocols used by messaging engines in the later version. This link can be used to access JMS resources that have a destination anywhere on the bus or on any other connected bus.
Property | Value |
---|---|
Name | Default.MQClientLink |
Description | Default MQ Client Link |
Queue manager name | WAS_nodeName_jmsserver |
Channel name | WAS.JMS.SVRCONN |
This figure shows an example single-node scenario after migrating the node to WebSphere Application Server Version 7.0. The JMS resources are now managed as Version 5 embedded messaging JMS resources implemented by the Version 7.0 default messaging provider. Also, a WebSphere MQ client link and bus queue have been created and assigned to the messaging engine, to enable JMS applications developed for WebSphere Application Server Version 5.1 to use the JMS resources.
Existing WebSphere Application Server Version 5.1 client applications using Version 5.1 connection factory and destination definitions use the WMQI wildcard convention. Such applications can connect to the default messaging provider and service integration bus, and automatically have their wildcard syntax mapped to the XPath convention when subscriptions are created. Any display of these subscriptions through the administrative interface of a later version shows the XPath syntax.
When upgrading from WebSphere Application Server Version 5.1, the Version 5 embedded messaging configuration scripts are retained, but have no influence on the default messaging provider in the later version, and fail if run. Do not run the scripts. Failure of the scripts can appear to be a failure of the installation of the later version, but no damage or action to the installation results from running the scripts.