A: modifier:
* Permission modifier: private, default, Protected,public
* Status modifier: static,final
* Abstract modifier: Abstraction
* B: Class:
* Permission modifier: default modifier, public
* Status modifier: Final
* Abstract modifier: Abstraction
* The most used is: public
* C: Member Variable:
* Permission modifier: private, default, Protected,public
* Status modifier: static,final
* The most used is: private
* D: Construction Method:
* Permission modifier: private, default, Protected,public
* The most used is: public
* E: Member Method:
* Permission modifier: private, default, Protected,public
* Status modifier: static,final
* Abstract modifier: Abstraction
* The most used is: public
* F: In addition to the combination of rules:
* Member variable: public static final
* Member Method:
* public static
* Public abstract
* Public Final
Java package, class permission access