Well China is worried by Indian ambitions to steal its land , and also terrorize other countries so it has to defend its friends and also its national interest .....
War if it happens will happen , I mean if we look at the Indian Army general's comments
Reference:
The Sentinel
As 2009 was coming to an end, Chief of the Army Staff General Deepak Kapoor indicated that India was revising its five-year-old military doctrine to maximize its military options in the Indian subcontinent and to reflect the reconfiguration of threat perceptions and security challenges. The two-front war strategy that was being deliberated was on simultaneously targeting China and Pakistan if a war happens. While revealing this he also outlined a few key elements of the doctrine. The announcement followed the November statement by General Kapoor about the likelihood of a limited war “under a nuclear overhang” in the subcontinent.
India is just inviting war on itself , we can only try to resolve the request