happens-before俗解： http://ifeve.com/easy-happens-before/
volatile关键字解析： https://www.cnblogs.com/dolphin0520/p/3920373.html
Java线程池ThreadPoolExecutor实现原理剖析：https://github.com/aCoder2013/blog/issues/28
java codeCache :https://blog.csdn.net/yandaonan/article/details/50844806
redis分布式锁：https://blog.csdn.net/l_bestcoder/article/details/79336986
equals和hashcode: http://www.cnblogs.com/aspirant/p/7079538.html