Resource Adapter (RAR) upgrade considerations
 Technote (troubleshooting)
 
Problem(Abstract)
Multiple versions of a stand-alone RAR (Resource Adapter archive) should not be installed on the same node because they share a common classloader.
 
Resolving the problem
Resource adapters (RARs) installed on a node and not packaged within an EAR share the same classloader. Therefore, if a newer version of a resource adapter uses the same package names, name collisions could result in unspecified behavior.
Exceptions such as InvalidClassCastException could be thrown, or there could be much more subtle indications. For example, properties set on one connection factory may be used by another connection factory instead, when the two connection factories are configured to respective resource adapters which differ only in content but not in package names.

Besides the resource adapter executable code, it could have other libraries which are installed. These too are not isolated when different versions of the resource adapter are installed, so similar conflicts arise.

Versioning support of resource adapters is not supported at this time. The recommended procedure for upgrading a resource adapter is as follows:
  1. Stop any applications which have resource references to a connection factory defined for the resource adapter.

  2. Note any configuration settings desired on the resource adapter and its connection factories.

  3. Delete the resource adapter. This removes the connection factories configured for that resource adapter.

  4. Install the newer resource adapter.

  5. Configure connection factories.

There are ways for multiple versions of a resource adapter to work in a WebSphere installation. If installed on separate nodes, the classloader conflict is not an issue since each version has its own classloader. A version of a resource adapter can be packaged as an embedded RAR within an application that needs to use that particular version. Such an embedded resource adapter can coexist with any number of similar versions if they are also packaged within separate application EAR files. A single stand-alone RAR version can coexist with any number of other RAR versions which are packaged within applications.
 
 
Cross Reference information
Segment Product Component Platform Version Edition
Application Servers Runtimes for Java Technology Java SDK
 
 


Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server > Java 2 Connectivity (J2C)
Operating system(s): Windows
Software version: 6.1
Software edition:
Reference #: 1200966
IBM Group: Software Group
Modified date: May 2, 2005