What does super mean in java

The super keyword in Java is used to access the constructor, methods and fields of the parent class: Member access: super() calls the parent class constructor. Method access: super.method() calls the parent class method. Field access: super.field accesses parent class fields.

super in Java

super is a keyword in Java that is used to access members of the parent class . In a subclass, use the super keyword to access the constructor, methods, and fields of the parent class.

Member access

• Constructor: Use super() to call the parent class constructor in the subclass constructor. This is typically used to initialize parent class members and implement polymorphism.
• Method: Use super.method() to call the method of the parent class. This is mainly used to override parent class methods or call parent class implementations.
• Field: Use super.field to access the fields of the parent class. It should be noted that if a subclass also has a field with the same name, the subclass field will be accessed first.

Usage

The super keyword is usually used in the following situations:

• Calling the parent class constructor to initialize the parent class members .
• Override parent class methods to achieve polymorphism.
• Access fields in the parent class that cannot be overridden or hidden in the subclass.

Example

class Parent {
    private int age;

    public Parent(int age) {
        this.age = age;
    }

    public int getAge() {
        return age;
    }
}

class Child extends Parent {
    public Child(int age) {
        super(age); // 调用父类构造函数
    }

    @Override
    public int getAge() {
        return super.getAge() + 1; // 覆盖父类方法并调用父类实现
    }
}

In this example, the subclass Child initializes the age field of the parent class by calling the constructor of the parent class Parent through super(age) . It also achieves polymorphism by calling the getAge() method of the parent class through super.getAge().

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