Question

Goal: Apply ideas about inheritance with Abstract classes

Assignment: Imagine that you are a mathematician that is creating a program to automatically generate shape objects. The concept of a shape means nothing on its own but begins to take shape ;) when you define its boundaries.

The Abstract class Shape has already been created for you. Shape defines the abstract method calculateArea and the concrete method displayShape which prints "This is a shape.".

Create two classes, Circle and Rectangle that meet the following requirements:

They can be instantiated

They have constructor methods that define the minimum properties for calculating the shape's area $($e$.$g$.$ you only need a circle's radius to calculate its area$).$ These should be integers.

They redefine the calculateArea method to calculate and return that shape's area.

They override the displayShape method to display "This is a $".$

$//$ Abstract class Shape, serving as a blueprint for various shapes

abstract class Shape $\{$

$//$ Abstract method to calculate the area, must be implemented by subclasses

public abstract double calculateArea$()$;

$//$ A concrete method to display the type of shape

public void displayShape$()\{$

System.out.println$("$This is a shape."$)$;

$\}$

$\}$

$//$ Write your code here. Please explain as well. Thank you!