Java关键字及其作用详解

参考：

JAVA关键字

https://blog.csdn.net/z1web/article/details/89068217

final关键字详解

https://baijiahao.baidu.com/s?id=1601084106055683243&wfr=spider&for=pc

Java并发编程：volatile关键字解析

https://www.cnblogs.com/dolphin0520/p/3920373.html

bigdicimal用法 decimal

https://blog.csdn.net/Jae_Wang/article/details/80632138