[Java] Object-oriented principles

https://zh.wikipedia.org/wiki/SOLID_(%E9%9D%A2%E5%90%91%E5%AF%B9%E8%B1%A1%E8%AE%BE%E8%AE%A1)

Initials	Refers to	concept
S	Single function principle	Single function principle I think the object should have only one single function concept.
O	Principle of opening and closing	Principle of opening and closing The concept of "software body should be open for extension, but closed for modification".
L	Richter substitution principle	Richter substitution principle The concept that "objects in the program should be replaced by its subclasses without changing the correctness of the program". Refer to  contract design .
I	Interface isolation principle	Interface isolation principle  The concept that "multiple specific client interfaces is better than one broad-purpose interface" [5] .
D	Dependence reversal principle	Dependence reversal principle It is believed that a method should follow  the concept of "depending on abstraction rather than an instance" [5] . Dependency injection is one way to implement this principle.