Interesting article on the Chinese military:
China’s potential for military aggression - upiasia.com
It's two years old but probably still has some relevance.
The idea that Chinese don't want a war seems to be a common assumption. I would suggest that the Chinese don't want a war that they might lose. It seems to me, that the Chinese have never had a problem rattling their sabre a little - mostly over US involvement with Taiwan. Yes, their focus is on their economy right now. But let's not confuse them with a great beneficial "how do we build a better world" country. China's historic view of itself is very self-centered (as much or more so than the US - I would suggest both countries view themselves as countries of "destiny").
I suspect that this is simply NK & SK spitting at each other. So long as none of the regional powers over react, I suspect this will settle down into the minor border dispute it is. IMHO, it is something serious but not imminently dangerous at this time. Kind of like a boiling pot that just needs to be watched.
Here's a question for you: If NK launches an attack (full frontal invasion) of SK - Currently, the US has ~ 28,500 personnel in SK - what should our response be? Do we fight? Evacuate US personnel to Japan? What if China supports the invasion? Either with personnel or material.
Yes, I think it is completely hypothetical, but I am just curious what everyone's reaction would be. I am torn - I wouldn't want
my son dying for SK, but we have basically told them "We got your back". Japan/Taiwan get invaded and that's a different story but hard for me to get worked up about Korea.