This is a RESEND because of mail server issues. Not sure if the original message went out. I saw a similar thread about this back in March but I am now seeing a similar exception being thrown. I am running 5.0.1. The error is thrown in my app after the change set listener determines there was a change with the rules package in the Guvnor. I have included the stack trace from the most recent time the exception was thrown. Hopefully someone can provide some additional information or a workaround. Has this problem been fixed in 5.1? If so, has 5.1 moved out of M2 state and into a CR state and when will it go into a full released state? Exception in thread "Thread-44" java.lang.OutOfMemoryError: GC overhead limit exceeded at org.drools.rule.GroupElement.<init>(GroupElement.java:44) at org.drools.rule.GroupElement.<init>(GroupElement.java:47) at sun.reflect.GeneratedConstructorAccessor61.newInstance(Unknown Source) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingCons tructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at java.lang.Class.newInstance0(Class.java:355) at java.lang.Class.newInstance(Class.java:308) at org.drools.rule.GroupElement.clone(GroupElement.java:267) at org.drools.rule.GroupElement.clone(GroupElement.java:279) at org.drools.rule.Rule.getExtendedLhs(Rule.java:518) at org.drools.rule.Rule.getTransformedLhs(Rule.java:545) at org.drools.reteoo.builder.ReteooRuleBuilder.addRule(ReteooRuleBuilder.ja va:98) at org.drools.reteoo.ReteooBuilder.addRule(ReteooBuilder.java:117) at org.drools.reteoo.ReteooRuleBase.addRule(ReteooRuleBase.java:362) at org.drools.common.AbstractRuleBase.addRule(AbstractRuleBase.java:618) at org.drools.common.AbstractRuleBase.addPackages(AbstractRuleBase.java:500 ) at org.drools.reteoo.ReteooRuleBase.addPackage(ReteooRuleBase.java:388) at org.drools.agent.impl.KnowledgeAgentImpl.rebuildResources(KnowledgeAgent Impl.java:416) at org.drools.agent.impl.KnowledgeAgentImpl.applyChangeSet(KnowledgeAgentIm pl.java:120) at org.drools.agent.impl.KnowledgeAgentImpl$ChangeSetNotificationDetector.r un(KnowledgeAgentImpl.java:538) at java.lang.Thread.run(Thread.java:619) Thanks.