Hi One and All, I used resource scanner in my program to update changes automatically. Every thing works fine. I had one method Method1 to create knowledge base. I had another method Method2 : with an infinite loop where i had a set of facts insert into in command list, and ksession.execute. Now i tested the application whether the changes are applying or not : After adding or modifying rule ,I validate and build package. Now from infinite loop i got an error at line ksession.execute(CommandFactory.newBatchExecution(cmds)); Exception in thread "main" java.lang.ClassCastException: pricing.specification cannot be cast to pricing.specification at org.drools.base.pricing.specification26362458$getSmsusage.getValue(Unknown Source) at org.drools.base.extractors.BaseObjectClassFieldReader.isNullValue(BaseObjectClassFieldReader.java:179) at org.drools.base.ClassFieldReader.isNullValue(ClassFieldReader.java:179) at org.drools.reteoo.CompositeObjectSinkAdapter$HashKey.setValue(CompositeObjectSinkAdapter.java:606) at org.drools.reteoo.CompositeObjectSinkAdapter$HashKey.<init>(CompositeObjectSinkAdapter.java:568) at org.drools.reteoo.CompositeObjectSinkAdapter.propagateAssertObject(CompositeObjectSinkAdapter.java:362) at org.drools.reteoo.ObjectTypeNode.assertObject(ObjectTypeNode.java:215) at org.drools.reteoo.EntryPointNode.assertObject(EntryPointNode.java:244) at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:330) at org.drools.common.NamedEntryPoint.insert(NamedEntryPoint.java:291) at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:886) at org.drools.common.AbstractWorkingMemory.insert(AbstractWorkingMemory.java:845) at org.drools.impl.StatefulKnowledgeSessionImpl.insert(StatefulKnowledgeSessionImpl.java:255) at org.drools.command.runtime.rule.InsertObjectCommand.execute(InsertObjectCommand.java:84) at org.drools.command.runtime.rule.InsertObjectCommand.execute(InsertObjectCommand.java:38) at org.drools.command.runtime.BatchExecutionCommandImpl.execute(BatchExecutionCommandImpl.java:155) at org.drools.command.runtime.BatchExecutionCommandImpl.execute(BatchExecutionCommandImpl.java:76) at org.drools.impl.StatelessKnowledgeSessionImpl.execute(StatelessKnowledgeSessionImpl.java:264) at net.treetechnologies.bss.ruleengine.PricingRules.evaluatePriceRules(PricingRules.java:159) at net.treetechnologies.bss.ruleengine.RunRule.price(RunRule.java:184) at net.treetechnologies.bss.ruleengine.RunRule.main(RunRule.java:50) Thanks and regards Srinivasa sanda -- View this message in context: http://drools.46999.n3.nabble.com/Exception-in-thread-main-java-lang-Clas... Sent from the Drools: User forum mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users