What is rewriting in java

What is overriding in java

The inheritance feature of a class in a Java program can generate a subclass , when a subclass inherits the parent class, it will have the non-private attributes (methods and variables) of the parent class. You can add your own attributes (methods and variables) to the subclass, and you can also extend the methods in the parent class to Enhancing one's own functions is called rewriting, also known as copying or overwriting.

The so-called method rewriting is the inheritance of methods in subclasses and parent classes. (Recommended tutorial: java tutorial)

The method that comes down has exactly the same method name, return value type, number of method parameters, and parameter type, so that it can be called method rewriting. .

// 这是父类的定义
public class Person {
    public void eat() {
        System.out.println("=====这是父类Person的eat方法=======");
    }
}
// 这是子类的定义
public class Student extends Person {
    @Override
    public void eat() {
        System.out.println("===这是子类Student的eat方法===");
    }
    // main方法测试
    public static void main(String[] args) {
        Student student = new Student();
        student.eat(); //输出：===这是子类Student的eat方法===
    }
}

After the subclass overrides the method of the parent class, the method in the subclass is called when instantiating the subclass, and the method of the parent class is as if it has been overwritten. If you need to call a method of the parent class in a subclass, use the super keyword in the subclass method to call the method of the parent class. The format is: super. The method name in the parent class.

Characteristics of method rewriting

In the subclass and the parent class, the method declaration is the same.

The method declaration of the subclass must be the same as that of the parent class. The parent class is the same

The method to be overridden by the subclass, the permission modifier of the method cannot be lower than that of the parent class (public, protected, default, private permissions increase in order)

Private of the parent class Methods, subclasses cannot override methods

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