How does China have so much money to lend?

How does China, a country that's often associated with strict economic controls and a large population, have the financial capability to lend such significant amounts of money to other nations and institutions? Are there specific economic policies or strategies that China has implemented that have allowed it to accumulate such a large pool of funds for lending? Is there a particular reason why China chooses to lend its money, and what are the potential benefits and risks associated with these lending activities?