I use a Ruleagent with the following params (rules.properties): localCacheDir=. url=. poll=30 name=eventexpertrules Here is my session initialization: RuleAgent agent = RuleAgent.newRuleAgent("/rules.properties"); RuleBase retValue = agent.getRuleBase(); final RuleBase ruleBase = agent.getRuleBase(); session = ruleBase.newStatefulSession(); DroolsLogger drlogger = new DroolsLogger(session); // add logger //Insert Event Processor Instance as global session.setGlobal("processor", this); Here is the stack trace of the thread that updates the rule base "Timer-2" daemon prio=3 tid=0x0000000002356800 nid=0x24 waiting for monitor entry [0xfffffd7fe28b7000..0xfffffd7fe28b7a20] java.lang.Thread.State: BLOCKED (on object monitor) at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:433) - waiting to lock <0xfffffd7feb474680> (a org.drools.reteoo.ReteooStatefulSession) at org.drools.base.FireAllRulesRuleBaseUpdateListener.beforeRuleBaseUnlocked(FireAllRulesRuleBaseUpdateListener.java:29) at org.drools.event.RuleBaseEventSupport.fireBeforeRuleBaseUnlocked(RuleBaseEventSupport.java:168) at org.drools.common.AbstractRuleBase.unlock(AbstractRuleBase.java:351) at org.drools.agent.PackageProvider.applyChanges(PackageProvider.java:73) at org.drools.agent.RuleAgent.refreshRuleBase(RuleAgent.java:320) at org.drools.agent.RuleAgent$2.run(RuleAgent.java:438) at java.util.TimerThread.mainLoop(Timer.java:512) at java.util.TimerThread.run(Timer.java:462) Here is the stack trace of my application that basically inserts facts and fires rules . "ActiveMQ Session Task" daemon prio=3 tid=0x0000000002564400 nid=0x142e in Object.wait() [0xfffffd7fe01dd000..0xfffffd7fe01ddaa0] java.lang.Thread.State: WAITING (on object monitor) at java.lang.Object.wait(Native Method) - waiting on <0xfffffd7feb49a9e0> (a org.drools.util.concurrent.locks.ReentrantLock$NonfairSync) at java.lang.Object.wait(Object.java:485) at org.drools.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:106) - locked <0xfffffd7feb49a9e0> (a org.drools.util.concurrent.locks.ReentrantLock$NonfairSync) at org.drools.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:195) at org.drools.common.AbstractWorkingMemory.getGlobal(AbstractWorkingMemory.java:397) at com.daxtechnologies.optima.fault.eventprocessor.Rule_EventForwarder_0ConsequenceInvoker.evaluate(Unknown Source) at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:550) - locked <0xfffffd7feb49a3f8> (a org.drools.common.DefaultAgenda) at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:514) at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:471) - locked <0xfffffd7feb474680> (a org.drools.reteoo.ReteooStatefulSession) at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:433) - locked <0xfffffd7feb474680> (a org.drools.reteoo.ReteooStatefulSession) at com.daxtechnologies.optima.fault.eventprocessor.fault.level2.maps.EventExpertProcessor.processEventVO(EventExpertProcessor.java:147) - locked <0xfffffd7feb474a18> (a com.daxtechnologies.optima.fault.eventprocessor.fault.level2.maps.EventExpertProcessor) at com.daxtechnologies.optima.fault.eventprocessor.fault.level2.maps.EventExpertProcessor.doProcessEvent(EventExpertProcessor.java:70) As you see both threads wait for something. thanks --zoly