https://tieba.baidu.com/p/7445127790#/
https://blog.csdn.net/codeyanbao/article/details/82875064
https://blog.csdn.net/sinat_16395609/article/details/120809204
一.双亲委派机制优势
● 避免类的重复加载
● 保护程序安全,防止核心API被随意篡改
○ 自定义类:java.lang.String
○ 自定义类:java.lang.ShkStart(报错:阻止创建 java.lang开头的类)