Java Object-oriented

Java object-oriented has 4 characteristics:

1 abstraction

Extracts the generality of an object, constituting an abstract class or interface, overriding an abstract method by an implementation class that inherits the class or interface of an abstract class.

2 inheritance

Subclasses inherit the parent class (the superclass, the base class), indicating that the subclass is a special parent class that has properties or methods that the parent class does not have. Super is a reference to the closest parent class object.

3 Package

Bind properties and methods to hide the concrete implementation of the class, and improve the security of the object.

4 polymorphic

Polymorphism refers to a method that invokes an object with different behavior. It is divided into compile-time polymorphism and run-time polymorphism, and the compile-time polymorphism is implemented by method overloading, and runtime polymorphism is implemented by means of method rewriting.

　　

Resources

Summary of abstract learning in Java

Java Inheritance Knowledge Summary

Summary of usage of this and super in Java

A detailed description of the Java package

Java-polymorphism, Method overloading

Method overloading Issues in Java

The difference between overloading and overriding in Java

Java Object-oriented