[rules-users] Inserting multiple objects of the same class as facts

Hello, I am facing a problem with the following code with Drools 5.0.1: I insert multiple objects as facts into my stateful session here: =============================================================== StatefulKnowledgeSession ksession = kbase.newStatefulKnowledgeSession(); /** mapTypes here is an array of MapType objects **/ for(int i=0;i<mapTypes.length;i++) { System.out.println("Inserting the fact type: " + mapTypes[i]); ksession.insert(mapTypes[i]); } ksession.insert(ldapLookupKey); ksession.insert(ldapResponseMap); ksession.fireAllRules(); ksession.dispose(); =============================================================== And here is my drools file: =============================================================== rule "LocalRecipient" when $myMapType : MapType( name == "LocalRecipient" ) $lookupKey : String() $ldapResponseMap : Map() eval( ((($ldapResponseMap.get("zimbraMailDeliveryAddress").equals($lookupKey)) || ($ldapResponseMap.get("zimbraMailAlias").equals($lookupKey)) || ($ldapResponseMap.get("zimbraMailCatchAllAddress").equals($lookupKey))) && ($ldapResponseMap.get("zimbraMailStatus").equals("enabled"))) ) then System.out.println("This LocalRecipient rule should work"); $myMapType.setQueryFilterCheck(true); end rule "VirtualMailboxDomain" when $myMapType : MapType( name == "VirtualMailboxDomain" ) $lookupKey : String() $ldapResponseMap : Map() eval( (($ldapResponseMap.get("zimbraDomainName").equals($lookupKey)) && ($ldapResponseMap.get("zimbraDomainType").equals("local")) && ($ldapResponseMap.get("zimbraMailStatus").equals("enabled"))) ) then System.out.println("This VirtualMailboxDomain rule should work"); $myMapType.setQueryFilterCheck(true); End =============================================================== Now the problem I am facing is, as long as I defined only rule001 above, it works like a charm and the MapType.QueryFilterCheck flag gets set to TRUE. As soon I put the rule002 above, I started getting a NullPointerException with the following lines in the stack trace. =============================================================== Caused by: java.lang.NullPointerException at com.aol.postfixcache.Rule_LocalRecipient_Rule_0.eval0(Rule_LocalRecipient_Rule_0.java:8) at com.aol.postfixcache.Rule_LocalRecipient_Rule_0Eval0Invoker.evaluate(Rule_LocalRecipient_Rule_0Eval0Invoker.java:23) at org.drools.rule.EvalCondition.isAllowed(EvalCondition.java:117) =============================================================== I tried different combinations along with an extensive search to see why I am getting this, but couldn't crack it. Appreciate your help. Regards, Murty.