Hi One and All, To over come from Knowledge agent rebuilding knowledge base with scanner/notifier does not work with declared fact caused java.lang.ClassCastException when change rule condition and declarative facts/events are used 1. I had a method which creates and loads the knowledge Agent. 2. I had a another method to execute rules which uses step 1 knowledge agent (work on infinite loop) 3. Using knowledge Agent Event listener for method afterChangeSetApplied() again i newly create and load knowledge agent. 4. while loading again got same error. Note: Can u please help me to create deep copy of knowledge agent which does not have references, i.e when i update rules the changes show not it should not be affected it should run with old copy. using java object clone method i can create deep copy but clone is not available for Knowledge agent. Thanks & Regards Srinivasa sanda -- View this message in context: http://drools.46999.n3.nabble.com/Create-a-deep-copy-of-KnowledgeAgent-tp... Sent from the Drools: User forum mailing list archive at Nabble.com.