See reproducer here: https://github.com/DuncanDoyle/drools-hang-issue

The reproducer is a very simple process with just a single rule-node. The rule file has 3 simple rules (don't do much, but I wanted to create a reproducer with the least amount of logic possible).

When I run this process in a simple unit-test, without using any jBPM persistence, RuntimeManager, RuntimeEngine, etc.,( i.e. I just use KieClasspathContainer and run the process using kieSession.startprocess) everything runs fine. See the ProcessWithoutJBPMTest class.

However, when I add jBPM to the mix (in this case via the JbpmJUnitBaseTestCase, once the process hits the ruleflow-node, it hangs somewhere in the rule execution. It happens both in the unit-test as in Business-Central in JBoss BPMSuite 6.3.0.GA. See the ProcessWithJBPMTest class.

What seems to happen is that 1 thread goes to 100% and starts filling up the heap, and once the heap is full, the GC threads kick in and the Java process goes to 650+% CPU utilisation, basically consuming all resources on my machine