I don't think India and China will involve in war with each other because they have so many things to loose (Economy, money, people and will suffer at least 10 years more for recovery.
But, In case of India and Pakistan war...
India :- We are happy with current scenario and line of control, no need to fight or war with pakistan. but, worst terrorist attack in India, It can be possible but very very little chance because we are economy power in the world and our growth rate is very good and our future will be better if we avoid war against any country. So, we have so many things to loose in case of war. So, we are bearing terrorist attack and making strong as possible so that no country dare try to destroy us.
Pakistan :- Wanted kashmir back... everyday they (politicians) start day with kashmir speech and ending day as well. they support terrorist but now they are suffering in home against terrorist bomb attack. they don't take chance direct war with India because know they can't win. other options are... make mujahidin and trained then send to India and also provide all kind of support. I don't need to prove my points because its already proved and world known.
In case of war India and pakistan, will China support pakistan and fight with India?...
Answer is... Big No, now they never going to take chance and war with India in any scenario. In future, we will be together on every matter because we are growing and we need each other. whatever, we want or not but China and India will not fight against each other.
My Point of view for pakistan :- Pakistan 1st establish his economy, education, railway, better job offers, IT and than try to establish military so that every country respect you better. I know one Pakistani friend in London, he is always says that I am Indian because of Pakistan image in current time. Kashmir.... you can't do any thing because It's not possible to get from India and it's reality, if u accept than it will be better for or otherwise after 50 years still you will be same as you now.....