Fighter Aircraft: Does the Chengdu J-20 make the F-35 obsolete?

What is the J-20?
An air superiority fighter?
An interceptor or interdictor?
An air support aircraft?
A nuclear fighter-bomber?

All we know about the J-20 is that it is (supposed to be) a low-observable aircraft, aka "stealth", that it doesn't have the engines that it really wants, and that it's bloody huge! The truth is no one knows what the J-20 is going to be, except the people who spec'd it out, and the people who are building it. They probably spend their coffee/tea breaks laughing about the rumour mills.

But does it make the F-35 obsolete?
This will be a highly speculative answer because no one really knows what it is. But what we do know is that the F-35 JSF (joint strike fighter) is a jack of all trades, master of (n)one. And that "one" is air support. I think of the F-35 as a stealth AV-8B Harrier II, the USMC's famous jump jet. In a BVR (beyond visual range) or WVR (within visual range) confrontation with an air superiority fighter, both the F-35 and AV-8B would have a very low chance of survival, assuming pilots are equally well-trained and in good condition.

If the J-20 is not an air superiority fighter, then it would only be competing on the military aircraft export market. The Americans have a much larger customer base than the Chinese, so the F-35 is winning this fight.