While Russia has been a major victim of China's program of stealing military technology, other countries have been more willing to share Russian military technology. When the Soviet Union was dissolved in 1991, 14 new nations were created from bits of the defunct empire. The new nations owned all Soviet weapons and defense factories that were on their territory. This provided China with many more opportunities to get Soviet military technology without having to deal with Russia (which is quite unhappy with China's plundering ways.)
Even Belarus, the former part of the Soviet Union that is most closely allied with Russia, has been eager to peddle Soviet military technology to China. Former Soviet factories in Belarus manufactured heavy trucks for transporting and launching large ballistic missiles. Thus Belarus is selling components and technology to assist China in building a transporter for its four ton DF11 ballistic missile. The Chinese WS2400 8x8 heavy duty truck used to carry the DF11 is very similar to Russian models.
Ukraine, which has frosty relations with Russia, has been exporting engines for China's K8 jet trainer, as well as engines for Chinese helicopters. Ukraine is also willing to sell technology, and send personnel to teach the Chinese how to build it. The Central Asian nations that were formerly part of the Soviet Union have also sold Soviet military technology to China.