Confusion.The Japanese Empire invaded China in the 1930s and it was Japan that started the war.while in this case, it is Vietnam that keeps provoking China.
Vietnam is a small country while China is a power. A small country should try to live peaceful with the giants. This is the right logic. Unfortunately, those stupid Vietnamese nationalists are pushing their Gov to a very hard position as to risk the future of the country.
China should go on with this project and should not stop just because there is little possibility that the western countries would buy these planes. Moreover, the Chinese domestic market is already very large.
Japan's territorial airspace is not the so-called Japan's Air Defence Identification Zone which China never admits. We do not enter their territorial airspace and we needn't ID ourselves in an international airspace.