MultithreadedTest.restRuleBaseConcurrentCreation sometimes has this error:

java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793)
at java.util.HashMap$ValueIterator.next(HashMap.java:822)
at org.drools.reteoo.EntryPointNode.updateSink(EntryPointNode.java:283)
at org.drools.reteoo.ObjectTypeNode.attach(ObjectTypeNode.java:276)
at org.drools.reteoo.builder.PatternBuilder.attachObjectTypeNode(PatternBuilder.java:186)
at org.drools.reteoo.ClassObjectTypeConf.<init>(ClassObjectTypeConf.java:94)
at org.drools.common.ObjectTypeConfigurationRegistry.getObjectTypeConf(ObjectTypeConfigurationRegistry.java:58)thread-6 failed: null

at org.drools.reteoo.Rete.assertObject(Rete.java:109)
at org.drools.reteoo.ReteooRuleBase.assertObject(ReteooRuleBase.java:207)
at org.drools.reteoo.ReteooWorkingMemory$WorkingMemoryReteAssertAction.execute(ReteooWorkingMemory.java:275)
at org.drools.common.AbstractWorkingMemory.executeQueuedActions(AbstractWorkingMemory.java:1398)
at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:1005)
at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:968)
at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:740)
at org.drools.integrationtests.MultithreadTest$RulebaseRunner.run(MultithreadTest.java:125)
at java.lang.Thread.run(Thread.java:619)