You don't manufacture them but you assemble them that is the difference & many parts of military tech come from the civil industry. I gave the example cause the sop of production at a standard are same across every industry and if those sop are followed in civil industry they can also be followed in military industry.
Okay for instance lets us take example of F35 & J20 what is the difference in 2 can you highlight them?
So how do you want to compare both fighters?
Nothing is declare by China as far as J20 is concern. Even no buddy knows the exact engine (russian/Chinese) they are using in final production model (if any) right now.