Re: [rules-users] java.lang.NullPointerException at org.drools.reteoo.ReteooFactHandleFactory.newFactHandle(ReteooFactHandleFactory.java:56)

Yes, to get the compiled package, compiled inside Guvnor , but this is the problem here. The compiled package is a serialized kPackage object . When you get this from guvnor, and put it inside your kBase, the object is simply deserialized. The ObjectTypeConf conf .getTypeDeclaration() will look in the kBase, and for guvnor compiled package this method returns null (don't know why). I think you may have a difference between your Guvnor version and the drools runtime version. You can either use the source got from guvnor ( http://localhost:8080/guvnor/rest/packages/org.dfms.model/source ) to build your kBase, and this should work fine.