Hello, I am facing this problem which I tried to resolve in all possible ways I could think of but situation is bit crazy here. I am creation knowledgebase object and putting it in servetCOntext object. On HTTP Request I create a new session, insert facts and fire all the rules. Every thing works well first time. But repeating the same (making another HTTP Request) throws exception shown below. If I create fresh knowledgebase every time problem doesn't show up at all. Please suggest where I might be going wrong. Google suggest that somewhere object are getting null. I verified that too. It doesn't seem to be the case. Regards, -Gaurav. org.drools.runtime.rule.ConsequenceException: [Error: unable to access field] [Near : {... Unknown ....}] ^ [Line: 1, Column: 0] at org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandle r.java:23) at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:943) at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:885) at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1086) at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:660) at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:627) at org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:183) -- View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/Getting-Exception-fir... Sent from the Drools - User mailing list archive at Nabble.com.