Design an abstract class called Shape. This class contains a single constructor that accepts a single numeric value that is used to calculate various values, one of which is area. Include an abstract mutator method called findArea to be used to find the area of any shape. Also provide a concrete accessor method that returns the area. Design two concrete classes, Circle and Square, that inherit the class Shape. Each of these classes finds the respective area; i. e. area of circle and area of square. You are responsible for providing any relevant variable(s).