Question

In the following java code

public class Person {
    int age = 18;
}

class Student extends Person {
    public Student() {
        this.age = 22;
    }

    public static void main(String[] args) {
        Student student = new Student();
        student.doSomthing();
    }

    void doSomthing() {
        System.out.println(this.age);
        System.out.println(super.age);// Here is something weird, at least for me till rightNow()
    }
}  

Why the super.age value is 22 , the same value as the sub-class’s age value, Isn’t it supposed to be 18;
Any help is appreciated.
Thanks in advance.

Answer 1

Age is a field in the super class. In the constructor of the subclass, when you say this.age = 22, you are updating the instance variable in the super class.

Try the following … I dont have a compiler handy but i think it might do what you are expecting.

public class Person {
    int age = 18;
}

class Student extends Person {

    int age; // Hides the super variable

    public Student() {
        this.age = 22;
    }

    public static void main(String[] args) {
        Student student = new Student();
        student.doSomthing();
    }

    void doSomthing() {
        System.out.println(this.age);
        System.out.println(super.age);
    }
}