They didn't make any such world class aircraft. Even the aircraft's own designer admits that it cannot compete and has a limited export market.
The chief designer of the Xiaolong, Yang Wei, said that the aircraft cannot compete with other aircraft on the market.
It's actually the CAC FC-1 Xiaolong, as Chengdu Aircraft Corporation did the majority of the design work on it. Meaning, it was developed by China -- Pakistan did not "manage" to do anything.
The quoted price for a single JF-17 unit is roughly $28 million USD. That's over 50% MORE expensive than an early-block F-16C. When compared with the significantly more expensive late model F-16 Block 52/Block 60/F-16I variants, you're still paying half the price, but getting a FAR less capable fighter. For that $28m price tag you get --- no AESA radar, ability to engage only two targets simultaneously, a sub-1.0 thrust-to-weight ratio in a clean configuration.... what a bargain!
Speaking of a bargain, nobody wants to buy it either. It was a dud at the Paris air show. The only interested nations thus far are Sri Lanka and Myanmar. Maaaayybee Argentina, if China allows the Argentines to have domestic production, AND assuming Kirchner stays in power. Egypt, Azerbaijan, Sudan, and Zimbabwe have all investigated it and turned up their noses. The biggest factor should be that China isn't even seriously considering it for any significant domestic buy.
How about parts? Russian engine; U.S., Chinese, French, and South-African ordnance, Chinese radar.... I'm not seeing exactly what Pakistan contributed.
It's cute that the Pakistani Air Force thinks they're playing with the big boys. But they are still at the kiddie table.
This is the opinion of Dan Rosenthal, a US aviation expert and thinktank