IBM Support

Manually generating Java core dumps for IIB or WMB DataFlowEngine

Technote (troubleshooting)


Custom Java code in a user-defined node or a JavaCompute node can cause the IBM Integration Bus (IIB) or WebSphere Message Broker (WMB) DataFlowEngine process to hang. Debugging these issues can be challenging because the DataFlowEngine process does not respond to configuration requests after it hangs. Forcing DataFlowEngine to generate a Java™ core dump for debugging problems may be helpful in resolving these kind of problems.

Diagnosing the problem

Java core dumps contain information about all of the Java threads that are running in a process, These can be used to diagnose problems such as lock conditions or non-terminating loops in a custom Java code.

Resolving the problem

To obtain diagnostic information by generating a Java core dump from a DataFlowEngine process, complete the following steps:

1. Create a message flow that contains an MQInput node, a JavaCompute node and an MQOutput node.

2. In your JavaCompute node, call the method.
3. Deploy your message flow to the execution group that contains the problem.
4. Recreate the conditions that result in the unresponsive DataFlowEngine process.
5. Examine the Java core dump to determine problems in your custom Java code
6. If the problem cannot be resolved, open a PMR and send the Java core dump to support for analysis.

This method is not supported on Solaris or HP platforms which do not use the IBM JRE, because they do not have access to the method.

Note that the collection of Java core dumps is an invasive activity and negatively impacts other processes that are running in the execution group. Use this technique only where necessary for debugging, and ensure that all message flows that contain the method are removed from your production Brokers after the problem has been diagnosed.

Related information

Triggering a java dump
Enabling a java dump

Cross reference information
Segment Product Component Platform Version Edition
Business Integration IBM Integration Bus 9.0 All Editions

Product Alias/Synonym

WMB MB WebSphere Message Broker MQ Integrator WBIMB WBI-MB MQSI WMQI

Document information

More support for: WebSphere Message Broker
Execution Group

Software version: 7.0, 8.0

Operating system(s): AIX, Linux, Windows

Reference #: 1618139

Modified date: 29 October 2014

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