I got it, I have to use Entrypoint in my DRL file otherwise it would give null pointer exception. I used like this- rule "Testing EntryPoint" when $cf : CashFlow() from entry-point "TransactionStream" then System.out.println($cf); System.out.println("Testing the transaction stream"); end From: Aman [mailto:boy18nj@gmail.com] Sent: Sunday, October 03, 2010 9:42 PM To: 'Rules Users List' Subject: WorkingMemoryEntryPoint NullpointerException? memoryEntryPoint is retrieved as null, what could be wrong here or do I need to do some special configuration in order to use working memory point streams? StatefulKnowledgeSession knowledgeSession = GivemeStatelessOrStateful .getStatefull("cashflow.drl"); WorkingMemoryEntryPoint memoryEntryPoint = knowledgeSession .getWorkingMemoryEntryPoint("TransactionStream");