Can China defeat Russia in war?

Answer :-

Opinion 1: ( By a Chinese)-

Oh, No. No. No, we can't.
I heard a story once. It said:
In the 1980s, the chief of the general staff asked a general:
"If USSR army attack Beijing, how long could you defend?"
"72 hours, sir!"
"hmm... When could you organize counter-attack?"
"Sorry, sir. What I said is the time how long USSR Army wipe out all of us. You have 72 hours to withdraw from Beijing."
I has inquired of my father (who used to be on active service) about whether the story is true. He answer: "No, not real. 48 hours is more correct. When I was serving in 张家口, the Beijing's north gate, our duty was serving as cannon fodder for 48 hours if USSR army attack Beijing."
For short, as a Chinese saying goes, 瘦死的骆驼比马大(A skeleton camel is bigger than a fat horse). China is a fat horse, we still have a long way to go.
That's my answer. 
Let's finish on a lighter note. In later 1980s, my father was serving in 张家口(Zhangjiakou), the city which will host the 2022 Winter Olympic Games. 口(kǒu)'s original meaning is mouth and extended meaning is gate, gates of the Great Wall. There are a lot of mountains in 张家口. My father said, the mountains have been hollowed by him and his comrades for building bomb shelters. There are hundreds of bomb shelters in the mountains. There are bomb shelters in every mountains under the Great Wall.
When you visit 张家口 during the Olympic Games, you will see the mountains. While you skiing, there may be a cave my father dug under your feet. Ha ha, just a joke. Hope the caves never be used. Cheer for Olympics, cheer for peace.

Opinion 2:-

At present I would say no, but China's military grows ever stronger each year. 
Russia has a large buffer between the border and any areas of consequence, a luxury China does not have.  Forward Russian units could lay waste to vast areas of population in northern China with quick scorched earth attacks and probably force a peace quickly even if China has the industry to out build Russia in the long term. 

Russia also has a better submarine fleet, and it could sink significant amounts of shipping heading into China, and without a friendly Russia, China lacks access to reliable land trade in volume.  Russia's trade on the other hand would be impossible for China to hinder, with such a large rail network with Europe and ports so far away for the limited long range elements of the Chinese navy to reach. 

If things went nuclear, obviously no one wins, but China would lose more, faster.  

Opinion 3:-

China can defeat Russia in PingPang, or, table tennis.LOL

But of course,Russian can  cut China into piece in a football game, or say it, soccer.

Well, war is too complex to be predicted, especially a nuclear war, there is no winner in a nuclear war.

So I think it's better to play pingpang or soccer.

Opinion 4:- 

Russia would win, then apologize to the rest of the world for utilizing  biological weapons to achieve its objective. I remember reading a Russian written proposed strategy for potential adversaries including China. The strategy proposed use of biological solution in China due to limited genetic diversity of population and its concentration in key areas. Making it a perfect candidate for such weapon use. 

This and few other topics were argued and agreed upon many times over by a bunch of my fathers friends and coworkers over drinks  at our house. Often the same exact point of genetics and centralized command&control and "industrial capacity" kept coming up (that's what made me remember and take what I was reading a bit more seriously). 

Normally a bunch of drunks persistently arguing about same strange topics wouldn't prove anything. In this case it just so happens that they all had Ph.D.s  in  bio-physics and during 80s Soviet Union days worked in a giant complex that for a while was marked "farming and agricultural assistance agency" . It had extraordinary high security presence for an agency that was meant to assist non yet existing class of people ( no independent farmers or farms in Soviet Union) and  inconveniently located between a giant bio engeneering  center and space research complex. Perhaps it was due to the lack of farmers and farms in the area that made labor force  of this agency develope unhealthy concern for other country's "industrial capacity" and how to apply biophysics to reduce it in case of a conflict. 

Soviet Union however, took assisting nonexistent  farmers and their not yet existing agricultural needs as very serious matter. So serious, that the whole city of 15000 was built to assist farmers!!! It had multitude of agriculture related agencies with labs, engeneering and research centers packed with scientists.... Even a space mapping center in case farmers on the moon need assistance.