BEIJING—The massive military parade in Beijing this week showcased China’s latest weapons, unveiling many to the public for the first time. But weapons experts say the systems on display showed hallmarks of China’s reputation for stealing technology and adapting it to its requirements. The show involved long, medium and short range missiles, a range of tanks and 200 fighter aircraft. The Chinese government said that all the equipment had been made indigenously, attesting to the success of the country’s military industrial capability and the estimated $145 billion spent on the military in 2015. “The parade was a bazaar of stolen...