[jboss-jira] [JBoss JIRA] Commented: (JBRULES-2346) insert: ConcurrentModificationException on iterate of ObjectTypeConfigurationRegistry#typeConfMap.
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https://jira.jboss.org/jira/browse/JBRULES-2346?page=com.atlassian.jira.p...
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Vince Adamo commented on JBRULES-2346:
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Upon further review and testing, a much more straightforward solution appears to be to use
the java.util.concurrent.ConcurrentHashMap as the type for
ObjectTypeConfigurationRegistry.typeConfMap, ie:
in ObjectTypeConfigurationRegistry.java:
public ObjectTypeConfigurationRegistry(InternalRuleBase ruleBase ) {
super();
this.ruleBase = ruleBase;
this.typeConfMap = new ConcurrentHashMap<Object, ObjectTypeConf>();
}
no other changes should be required.
insert: ConcurrentModificationException on iterate of
ObjectTypeConfigurationRegistry#typeConfMap.
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Key: JBRULES-2346
URL: https://jira.jboss.org/jira/browse/JBRULES-2346
Project: Drools
Issue Type: Bug
Security Level: Public(Everyone can see)
Components: drools-core
Affects Versions: 5.0.1.FINAL
Reporter: Olexandr Demura
Assignee: Mark Proctor
Attachments: EntryPointNode.java, ObjectTypeConfigurationRegistry.java
Very rare exception occurs in multi-threaded environment, each thread processes series of
rule evaluations with recreation of StatefulSession after each:
java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:1091)
at java.util.HashMap$ValueIterator.next(HashMap.java:1122)
at org.drools.reteoo.EntryPointNode.updateSink(EntryPointNode.java:285)
at org.drools.reteoo.ObjectTypeNode.attach(ObjectTypeNode.java:279)
at
org.drools.reteoo.builder.PatternBuilder.attachObjectTypeNode(PatternBuilder.java:234)
at org.drools.reteoo.ClassObjectTypeConf.<init>(ClassObjectTypeConf.java:93)
at
org.drools.common.ObjectTypeConfigurationRegistry.getObjectTypeConf(ObjectTypeConfigurationRegistry.java:58)
at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:849)
at org.drools.base.DefaultKnowledgeHelper.insert(DefaultKnowledgeHelper.java:114)
at org.drools.base.DefaultKnowledgeHelper.insert(DefaultKnowledgeHelper.java:108)
Problem is caused by cyclic dependency.
ObjectTypeConfigurationRegistry#getObjectTypeConf(EntryPoint, Object)
creates ClassObjectTypeConf to put into ObjectTypeConfigurationRegistry#typeConfMap,
creation code relies on EntryPointNode#updateSink(ObjectSink, PropagationContext,
InternalWorkingMemory),
which iterates on ObjectTypeConfigurationRegistry#typeConfMap.
I can't reproduce it on 5.1.0.M1 now, but because of rare reproduction.
Source looks like have this bug yet.
Used workaround for it:
EntryPointNode#updateSink(ObjectSink, PropagationContext, InternalWorkingMemory) iterates
on copy of ObjectTypeConfigurationRegistry#typeConfMap:
for ( ObjectTypeConf objectTypeConf :
wmEntryPoint.getObjectTypeConfigurationRegistry().values() ) {
->
for ( ObjectTypeConf objectTypeConf : new ArrayList<ObjectTypeConf>(
new wmEntryPoint.getObjectTypeConfigurationRegistry().values() )) {
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