The plane looks unfinished to me. While it is in junkyard now, why do they need to cover it so well?
A fast question: Didn't China promise stop copying Russian technology which means the end of J-11B?
The plane is only used for stress testing purposes. They hang those weights, then put the plane on a machine that will try to shake it to pieces. After this test, you can't use the airframe anymore, as its all going to be structurally worn out.