I just upgraded to drooling 5 and xml rules won't load

Question

When upgrading to drool 5, valid drool 4 xml rules do not work. Drools just throws a useless null pointer exception. What is the problem?

Answer 1

The problem is that Drools 5 has changed the namespace. Replace xmlns = "http://drools.org/drools-4.0" with xmlns = "http://drools.org/drools-5.0" and at least the simple rules you need.

I hope this helps save someone from the headache that I just dealt with this undocumented change.