Apparently you haven't been paying attention to the South China Sea. China has been taking territory for years, ships have been sunk.
China has also been predatory lending to other countries like Macedonia. TL;DR:
1) Macedonia agreed to an infrastructure project that costs more than Macedonia's economy makes in a year.
2) Macedonia was told no less than two times the project will never pay for itself in terms of economic activity.
3) China swooped in with their own reports that conflicted with #2, they offered a massive loan to start construction with two conditions: the majority of labor had to be performed by Chinese (as in forced immigration/settlement in Macedonia) and if Macedonia ever fails to make interest payments on the loan, China will own the project forever.
4) The project is about 1/3 complete and has run Macedonia into the ground.
5) Now
Macedonians are protesting their government that signed a bad deal with China and collapsed their economy.
This is how China wages war: extends one hand in peace while the other hand is ready to drive a dagger in your neck.
Chinese Spending Lures Countries to Its Belt and Road Initiative
China didn't have money to do these things in the first place. It took on debt to fund the projects. The tariffs and economic instability that it brought are making China's debt load punishing because China's economy is literally powered by trade with other countries. No more stealing industry from other countries means the factories that created a middle class in China no longer have orders to produce. No orders means letting people go. People with out pay have to go back to the farms to work. Middle class is quickly turned back to impoverished. This leads to unrest. China likely has 10 contingency plans to protect the Communist Party from uprisings for every contingency plan they have for the USA.