Why did the Chinese military go into the saving mode for the last 20 years?

&#x200B;<br><br>The Chinese military used to be very aggressive towards other nations. There were several Chinese invasions into Korean peninsula. China also invaded India in 1962 and has been claiming a large part of India's territory. China has also been in a state of war with Taiwan since 1949. There was also the Sino Soviet border war in 1969. <br><br>But since around the 80s or 90s, the Chinese military has stopped being aggressive. It has stopped invading other nations and has even helped other nations in a big way in times of need. For example China helped Indonesia after the 2004 tsunami and helped Pakistan after the 2005 earthquake.<br><br>Also since the rise of Xi Jinping, China has once again become aggressive and has started invading other nations. Like the Chinese invasion of India in 2020.<br><br>So why did the Chinese military go into a saving mode for around 20 years?