[ https://issues.jboss.org/browse/DROOLS-4413?page=com.atlassian.jira.plugi... ] Jesse White commented on DROOLS-4413: ------------------------------------- [~mfusco] thanks for taking the time to look at this. Good point. I've changed the test to make sure `fireUntilHalt` is called before we halt the session. {code:java} // Create a dedicated thread to fire KieSession kieSession = base.newKieSession(); CountDownLatch latch = new CountDownLatch(1); Thread t = new Thread(() -> { latch.countDown(); System.out.println("Firing."); kieSession.fireUntilHalt(); System.out.println("Halted."); }); t.start(); // Wait for the thread to start firing latch.await(); Thread.sleep(250); {code} When I run the test in a loop, I can still reproduce the problem after about 30 runs or so. Stack for the thread looks like the following: {noformat} "Thread-14" #40 daemon prio=5 os_prio=0 tid=0x00007fa2c0085000 nid=0x154d3 in Object.wait() [0x00007fa3202aa000] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <0x00000000f125e8d0> (a java.lang.Object) at java.lang.Object.wait(Object.java:502) at org.drools.core.common.DefaultAgenda$ExecutionStateMachine.waitInactive(DefaultAgenda.java:1375) at org.drools.core.common.DefaultAgenda$ExecutionStateMachine.waitAndEnterExecutionState(DefaultAgenda.java:1368) at org.drools.core.common.DefaultAgenda$ExecutionStateMachine.toFireUntilHalt(DefaultAgenda.java:1336) - locked <0x00000000f125e8d0> (a java.lang.Object) at org.drools.core.common.DefaultAgenda$RestHandler$FireUntilHaltRestHandler.handleRest(DefaultAgenda.java:1139) at org.drools.core.common.DefaultAgenda.fireLoop(DefaultAgenda.java:1074) at org.drools.core.common.DefaultAgenda.internalFireUntilHalt(DefaultAgenda.java:991) at org.drools.core.common.DefaultAgenda.fireUntilHalt(DefaultAgenda.java:983) at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireUntilHalt(StatefulKnowledgeSessionImpl.java:1369) at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireUntilHalt(StatefulKnowledgeSessionImpl.java:1348) at org.drools.compiler.integrationtests.WhatsWrongWithMeTest.lambda$canReturnWhenHalted$0(WhatsWrongWithMeTest.java:81) at org.drools.compiler.integrationtests.WhatsWrongWithMeTest$$Lambda$60/1688271262.run(Unknown Source) at java.lang.Thread.run(Thread.java:748) {noformat} This is consistent with the behavior we've been seeing in 7.7.0.Final, which is what led us to start investigating this in the first place. !intellij-test-failure.png|thumbnail! -- This message was sent by Atlassian Jira (v7.12.1#712002)