Showing off?! I think the same, they are just testing each others there. Tension between India and China are nothing new, they had a few conflicts before, but still India faces trade imbalance heavily in favor of China. It's better this to not grow in something bigger, two nuclear armed countries can make a lot of damage if they get in the fight!
From what i read and understand the tensions between China and India were not prevalent for decades and only recently there is some sort of border issue between both these nations, they had a full blown war more than four decades earlier when none of them were having nuclear warheads and now things have changed and both have massive nuclear warheads and if both these countries starts provoking each other then we might see a full out war and the rest of the countries joining either sides, but i am certain that the international body will find a solution for their aggitation and sort them out amicably.