[jboss-jira] [JBoss JIRA] Commented: (JBRULES-2797) HashTableIterator of AbstractHashTable is not Thread Safe

HashTableIterator of AbstractHashTable is not Thread Safe ---------------------------------------------------------- Key: JBRULES-2797 URL: https://issues.jboss.org/browse/JBRULES-2797 Project: Drools Issue Type: Bug Security Level: Public(Everyone can see) Components: drools-core, drools-core (flow) Affects Versions: 5.1.1.FINAL, FUTURE Environment: N/A Reporter: Anatoly Polinsky Assignee: Mark Proctor Labels: drools-core, drools-flow, thread-safety Attachments: AbstractHashTable-thread_localing_a_table_HashTableIterator_s_row_and__entity_.patch Original Estimate: 1 hour Remaining Estimate: 1 hour public static class HashTableIterator has a shared state that gets inconsistent when multiple threads work on the getting the next entity: public Object next() { if ( this.entry != null ) { PART 1 >> this.entry = this.entry.getNext(); } // if no entry keep skipping rows until we come to the end, or find one that is populated while ( this.entry == null && ++this.row < this.length ){ PART II >> this.entry = this.table[this.row]; } return this.entry; } In "PART 1", the race condition causes "this.entry" be NULL in "this.entry.getNext()", and throws the exception below. In "PART 2", the race condition causes inconsistent state of "this.row", and throws multiple exceptions, but mostly the one that is described in: https://jira.jboss.org/browse/JBRULES-2794 java.util.concurrent.ExecutionException: org.drools.RuntimeDroolsException: Unexpected exception executing action org.drools.reteoo.ReteooWorkingMemory$WorkingMemoryReteAssertAction@1ff323 at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:222) at java.util.concurrent.FutureTask.get(FutureTask.java:83) at org.custom.workflow.stress.test.WorkflowStressTest.shouldRunFlow(WorkflowStressTest.java:49) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20) at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74) at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:82) at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:240) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184) at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31) at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) at org.junit.runners.ParentRunner.run(ParentRunner.java:236) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:180) at org.junit.runner.JUnitCore.run(JUnitCore.java:157) at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:94) at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:192) at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:64) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at com.intellij.rt.execution.application.AppMain.main(AppMain.java:115) Caused by: org.drools.RuntimeDroolsException: Unexpected exception executing action org.drools.reteoo.ReteooWorkingMemory$WorkingMemoryReteAssertAction@1ff323 at org.drools.common.AbstractWorkingMemory.executeQueuedActions(AbstractWorkingMemory.java:1473) at org.drools.common.AbstractWorkingMemory.startProcess(AbstractWorkingMemory.java:1631) at org.drools.impl.StatefulKnowledgeSessionImpl.startProcess(StatefulKnowledgeSessionImpl.java:318) at org.drools.command.runtime.process.StartProcessCommand.execute(StartProcessCommand.java:99) at org.drools.command.runtime.process.StartProcessCommand.execute(StartProcessCommand.java:38) at org.drools.persistence.session.SingleSessionCommandService.execute(SingleSessionCommandService.java:285) at org.drools.command.impl.CommandBasedStatefulKnowledgeSession.startProcess(CommandBasedStatefulKnowledgeSession.java:193) at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:191) at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:692) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:89) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:625) at org.custom.workflow.stress.test.WorkflowRunner.call(WorkflowRunner.java:38) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303) at java.util.concurrent.FutureTask.run(FutureTask.java:138) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:662) Caused by: java.lang.NullPointerException at org.drools.core.util.AbstractHashTable$HashTableIterator.next(AbstractHashTable.java:312) at org.drools.reteoo.EntryPointNode.updateSink(EntryPointNode.java:323) at org.drools.reteoo.ObjectTypeNode.attach(ObjectTypeNode.java:303) at org.drools.reteoo.builder.PatternBuilder.attachObjectTypeNode(PatternBuilder.java:257) at org.drools.reteoo.ClassObjectTypeConf.<init>(ClassObjectTypeConf.java:92) at org.drools.common.ObjectTypeConfigurationRegistry.getObjectTypeConf(ObjectTypeConfigurationRegistry.java:68) at org.drools.reteoo.Rete.assertObject(Rete.java:111) at org.drools.reteoo.ReteooRuleBase.assertObject(ReteooRuleBase.java:280) at org.drools.reteoo.ReteooWorkingMemory$WorkingMemoryReteAssertAction.execute(ReteooWorkingMemory.java:360) at org.drools.common.AbstractWorkingMemory.executeQueuedActions(AbstractWorkingMemory.java:1471) ... 24 more