J2EE Connector Architecture migration tips
Previous WebSphere Application Server versions provided an initial implementation
of the J2EE Connector Architecture (JCA) specification, Version 1.0. This
implementation provided basic run time support based on the final JCA 1.0
Specification, but it was not a complete implementation.
The product now provides a complete implementation of the JCA 1.0 Specification,
which supports:
If you move from one of the earlier implementations of the J2EE Connector
Architecture to the current implementation, be aware of the following:
- This version supports the res-sharing-scope tag within the resource
reference (resource-ref) element. This tag was not available in previous versions
and defaulted to shareable connections. Version 5.0 supports both shareable
and unshareable connections.
- The current product supports the Web container. Both enterprise bean
and Web components can utilize the J2EE Connector Architecture.
- Both connection handle usage patterns (get/use/close and get/use/cache)
are supported. The get/use/close pattern indicates that a connection is retrieved,
used, and closed all within the same transaction or method boundary. The
get/use/cache pattern indicates that you can cache a connection across transaction
or method boundaries.
- The current version supports additional authentication mechanisms. The
capability to support Options A and C per the JCA specification is provided,
as well as support for res-auth settings of either Application or Container.
In previous versions, the res-auth setting was basically ignored,
therefore it was treated as if res-auth was set to Application.
If your existing applications had res-auth set to Container,
they might behavior differently if you install them into a current environment
without any changes.
- You can no longer specify pool and subpool names. The pool name is based
on the data source or connection factory's Java Naming and Directory Interface
(JNDI) name. Subpools were eliminated to provide better performance.
Migration issues for the combination of Web services and JCA connectors
For applications that use WebServices and JCA Connectors, there are some
additional points to be aware of:
- Applications generated on WebSphere Studio Application Developer -- Integration
Edition Version 4.1.1 can run on WebSphere Application Server Version 4.0.4
and WebSphere Application Server Enterprise Version 4.1.
- Applications generated on WebSphere Studio Application Developer -- Integration
Edition Version 5.0 can run on WebSphere Application Server Version 5.0 and
WebSphere Application Server Enterprise Version 5.0.
- Applications generated on WebSphere Studio Application Developer -- Integration
Edition Version 4.1.1 can run unchanged on WebSphere Application Server Enterprise
Version 5.0, but can only run on WebSphere Application Server Version 5.0
if the applications are regenerated using WebSphere Studio Application Developer
-- Integration Edition Version 5.0 tools.
This limitation is because of the wsd14j.jar file. As delivered
in WebSphere Application Server Enterprise Version 4.1, the file is not fully
compliant with JSR 110 (JSR 110 was not final at the time that 4.1 shipped).
The wsd14j.jar file shipped with WebSphere Application Server Version
5.0 is compliant. However, because most of the classes have the same package
names and interfaces, BUT NOT ALL, the two wsd14j.jar files cannot
co-exist in the same WebSphere Application Server installation.
Migration involving first-time use of connection pooling
If you are upgrading to WebSphere
Application Server V5.x from a version prior to V5.0, be aware of the run-time
behavior changes that your applications might incur because of the new connection pooling feature in the product.
Although not required by the J2EE architecture, connection pooling support
is provided by the connection management component of WebSphere Application
Server to help improve the performance of getting and using connections to
a backend, such as a database or transaction resource manager (CICS or IMS,
for example). The connection pooling support is provided, individually, to
every data source and connection factory that you configure. The properties
associated with each connection pool have default values that are sufficient
for most application server environments. However, in some cases, the default
values might not meet the needs of application connection requests, and result
in problems such as ConnectionWaitTimeout exceptions.
Therefore you must consider the application requirements of each data source
and connection factory that you configure, and set the corresponding connection
pool properties appropriately. The Connection pool settings topic
provides reference for setting these properties.

Resource adapter
Connection factory
Data sources
Unshareable and shareable connections
Connection handles
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jcamigt
Last updated: Jun 21, 2007 8:07:48 PM CDT
WebSphere Business Integration Server Foundation, Version 5.0.2
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