Arbitral Tribunal has no jurisdiction to deal with the case of the Philippines against China over claims in South China Sea

The Arbitral Tribunal of the United Nations constituted under Annex VII of the 1982 UN Convention on the Law of the Sea, presided by Thomas Mensah, international maritime and environmental law advisor, is on its way to deal with the case brought about by the Philippines government against China. As a general principle, if one of the parties to the dispute does not appear before the tribunal - before making its award - the tribunal must first satisfy itself that it has jurisdiction over the dispute.

This finding of the jurisdictional question can only be based on the provisions of UNCLOS. So when China has refused to accept the jurisdiction of the tribunal according to relevant provisions of UNCLOS, how will it decide its jurisdiction over this case?