Rule of law is necessary, not sufficient, for justice. You cannot have justice if you do not know what behavior will get you punished, and you cannot know what behavior will get you punished if the government can act arbitrarily with impunity.

Edit in reply to below: the issue in China is precisely that the government's response to criticism is unpredictable. If Xi Jinping criticizes Chinese policy, that means a new policy is now in place. If a random guy on the street criticizes Chinese policy... maybe he'll be fine? Or maybe not. Depending on where and to whom he says it and how nice public officials are feeling that day.

And the problem with China is not that it's lacking rule of law, but that the laws are unjust. It is easy to predict what will happen to you if you criticize the government.