Debug log classes for object queue issues

When troubleshooting object queue problems, it is sometimes useful to turn on additional debug logging to help facilitate the investigation.

The following is a list of key classes, which provide useful debug information for runtime object queue components:

nexj.system.*: Set to DUMP level logging in order to make the DEBUG level logging visible to the classes in this list.
nexj.core.rpc.queueing.ObjectQueueDispatcher: Logs information about the dispatcher activity.
nexj.core.rpc.queueing.ObjectQueueMessage: Logs information about the state of the object queue messages.
nexj.core.rpc.queueing.ObjectQueueSemaphore: Logs information about the object queue concurrency controls.
nexj.core.rpc.queueing.ObjectQueueConnection: Logs all exceptions caught on threads entering the application code from any resource adapter. The messaging engine relies on a resource adapter for thread management, so this can be a useful starting point if you suspect a failure within the engine.
nexj.core.rpc.queueing.ObjectQueueConsumer: Logs information about object queue thread activity.
nexj.core.rpc.queueing.ObjectQueueConsumerPool: Logs information about object queue thread activity.

If the object queue engine determines that a preemptive fail-over of the dispatcher is required, this activity is logged as WARN messages in the log files as follows:

Object queue dispatcher node "NodeName" is overloaded
Unsuccessful pre-emptive fail over attempt from node "NodeName", cause of failure