Clam down, there're many ways for China to expand it's influence other than war. Plus, India and China both have nuclear weapons, meaning death trigger for everyone on earth, you don't want to touch that.
Tibet on the other hand is a very long, complex and different story (and South China Sea is whole another different one), I don't think they belongs to the same topic.
I can pretty much tell you that, in China, nobody think of India or Vietnam etc as enemy. Instead, they're the MARKET we can sell our product to. Which, guess what, that's what everybody do now, rather than thinking about war all days.
So, why not trading and be good at it?