Five weapons that China stole or copied

Beijing [China], April 28 : China has long supplemented legitimate transfers and domestic innovation with industrial espionage helping to compete with the U.S. or the U.S.S.R. in the production of advanced military technology.
People's Republic of China (PRC) has a well-established habit of pilfering weapons technology from Russia and the United States, reported The National Interest.
Beijing's spies have become ever more skillful and flexible in their approach over the years and helped China steal or copy, in whole or in part, five advanced weapon technology systems.
These consist of J-7, J-11, J-31, UAVs, and night-vision technology.
In 1961, the Soviets transferred blueprints and materials associated with its new MiG-21 interceptor to China. The Chinese worked from the blueprints and other materials, and eventually produced the J-7, a virtual copy of the MiG-21, reported The National Interest.
The Chinese eventually sold the J-7 (F-7 export variant) in direct competition with the MiGs sold by the Soviets.
1990s saw several huge arms deals between Moscow and Beijing. One of the most important involved the sale, licensing, and technology transfer of the Su-27 "Flanker" multirole fighter.
Russians claim that the Chinese began violating licensing terms almost immediately, by installing their own avionics on Flankers (J-11, under Chinese designation), reported The National Interest.
American analysts suspected that China was stealing information associated with the F-35. The likely reality of this theft became clear when information about the J-31 stealth fighter became available. The J-31 looks very much like a twin-engine F-35, without the VSTOL capabilities of the F-35B.
The J-31 also presumably lacks much of the advanced avionics that have the potential to make the F-35 a devastating fighter, reported The National Interest
In 2010, China lagged woefully behind the United States in unmanned aerial vehicle (UAV) technology. Since that time, the Chinese have caught up, and are now producing drones capable of competing with US models on the international arms market.
According to US intelligence, Chinese hackers appropriated technology from several sources, including the US government and private companies (General Atomics) associated with the production of UAVs. The newest Chinese UAVs closely resemble US aircraft visually and in performance, a remarkable turn-around time for China's aviation industry, reported The National Interest.
After the Vietnam War, the United States military decided that it would invest heavily in an effort to "own the night" to make advances in night vision technology, including equipment that allowed individual soldiers, armoured vehicles, and aircraft to see and fight in the dark. This equipment has given the US a huge advantage in several conflicts since the 1980s.
China is seeking to end this advantage, and has geared some of its espionage efforts towards acquiring and replicating US tech in this area. This has included some cyber-theft, but also several old-style ops in which Chinese businessmen illegally acquired export-controlled tech from US companies, reported The National Interest.
The United States has become increasingly aggressive about slowing down or halting China's industrial espionage efforts. This has included indictments of PLA officers, broad condemnations of Chinese spying, and targeted reprisals against some Chinese firms.