Java Management Extensions interoperability

WebSphere Application Server V6 implements Java Management Extensions (JMX) V1.2, while WebSphere Application Server V5 implements JMX V1.0.

Due to the evolution of the JMX specification, the serialization format for JMX objects, such as the javax.management.ObjectName object, differs between the V5 implementation and the V6 implementation. The V6 JMX run time is enhanced to be aware of the version of the client with which it is communicating. The V6 run time makes appropriate transformations on these incompatible serialized formats to support communication between the different version run times. A V5 wsadmin script or a V5 administrative client can call a V6 deployment manager, node, or server. A V6 wsadmin script or a V6 administrative client can call a V5 node or server.

When a V5 wsadmin script or a V5 administrative client calls a V6 MBean, the instances of classes that are new in V6 cannot be passed back to V5 because these classes are not present in the V5 environment. The problem occurs infrequently. However, it usually occurs when an exception embeds a nested exception that is new in V6. The symptom is usually a serialization exception or a NoClassDefFoundException exception.

Due to changes in the JMX implementation from V5 to V6, different exceptions are created when a method on an MBean is invoked for V5 than when a method on an MBean is invoked for V6. For example, when a method gets or sets an unknown attribute for V5, the MBeanRuntimeException exception is created. When a method gets or sets an unknown attribute for V6, the MBeanException exception that wraps a ServiceNotFoundException exception is created.

An instance of a user-defined class that implements the Serializable interface that is passed as a parameter or return value during MBean invocation, or sent as part of a notification, cannot contain a non-transient instance variable that is in the javax.management.package package. If the instance does, it cannot be properly deserialized when passed between V5 and V6 run times.

Due to changes in the supported format for the ObjectName class from V5 to V6, the configuration ID in V6 contains a vertical bar (|), whereas in V5, the ID contains a colon (:). This change is reflected in the output for wsadmin clients. For example, for a V5 client, the output is

wsadmin>  $AdminConfig list Cell
     DefaultCellNetwork(cells/DefaultCellNetwork:cell.xml#Cell_1)

whereas for a V6 client, the output is

wsadmin>  $AdminConfig list Cell
     DefaultCellNetwork(cells/DefaultCellNetwork|cell.xml#Cell_1)

The change to the configuration ID generally is not a problem because configuration IDs are generated dynamically. When a V5 client passes a configuration ID that contains a colon, the JMX run time, for upward compatibility, automatically transforms the configuration ID that contains a colon into a configuration ID that contains a vertical bar. Similarly, a reverse transformation is performed for backward compatibility.

Do not save the configuration ID and then try to use it later. Only query the ID and use it.

 



 

 

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IBM is a trademark of the IBM Corporation in the United States, other countries, or both.