Well,yes and no. There is no separate queue for J class,but you can ask the RJ transit desk staff (assuming you are flying RJ) to quejump on your behalf,but unless the queue is really long I would not do that.

If coming from landside,RJ has a top class (one of the best in the world IMO) facility,whereby premium pax (RJ J cl+OWR/above) can use the Crown Class check in lounge far away from the general check in,with its own immigration and security checkpoints,which guarantee a very swift clearance. This facility is only for pax on RJ metal,other airline pax (including QR/BA) check in in the general area with no fast track whatsover.