I'm am trying to add my own ObjectMarshallingStrategy by setting the relevant environment variable:
env.set(EnvironmentName.OBJECT_MARSHALLING_STRATEGIES, new org.drools.marshalling.ObjectMarshallingStrategy[] {new SomeMarshallingStrategy()});
So far this doesn't seem to have any effect, it still goes to the ProtobufMarshaller and I'm still looking into it. But I wanted to report it here in case I'm on the wrong track. Or if someone know why setting this environment variable is not having any effect.