interesting article from a Russian magazine speculating that perhaps instead of a fighter the J-20 might perhaps be a "Carrier Killer". This theory would fit with how the J-20 is designed, because the J-20 is optimized for long range, subsonic speeds to Mach 1.6 and has a large amount of room inside for anti-ship cruise missiles.
Another reason this might fit is the fact the Chengdu's rival Shenyang Aircraft Corporation has yet to come out with a stealth fighter design. This would also fit in that Shenyang produced and produces most of China's indigenous fighter aircraft. Aviation Week had an interesting piece about this, that speculates about some of the other Chinese stealth designs coming down the pipe.
If the J-20 is designed for the anti-ship role this fits with China's paranoia when it comes to American aircraft carriers. Especially with the recent development of the DF-21D (CSS-5 Mod-4) and cruise missiles like the C-803 (YJ-83).
Photo Credit: Wikipedia