Java Subclass uses super.tostring() but not superclass' method in it. Why?

Question

I am doing OOP exercises from https://www3.ntu.edu.sg and I cant figure out one inheritance problem. We have 2 classes: superclass circle and subclass cylinder extends circle .

Circle:

public double getArea() {
        return Math.PI*radius*radius;
}
public String toString() {
        return "Circle Area: "+this.getArea()";
}

Cylinder extends Circle

@Override
    public double getArea() {
        // TODO Auto-generated method stub
        return super.getArea()*2+super.getCircumference()*height;
    }

    @Override
    public String toString() {
        return "Cylinder["+super.toString+"]"+"Cylinder area="+getArea()+"]";
    }

new object type Cylinder prints super.toString() using getArea() from the Cylinder class - printing both areas the cylinder areas. How can I make it use superclass ( Circles ) getArea() in super.toString ?

Thanks!

Answer 1

During runtime this represents the current instance of the object and this is a Cylinder with his getArea() method. Therefore inheritance does not help us here.

A workaround can be to change the Circle class this way:

private double getCircleArea() {
        return Math.PI*radius*radius;
}

public double getArea() {
        return getCircleArea();
}

public String toString() {
        return "Circle Area: " + this.getCircleArea();
}