Hierarchy

public class Hierarchy {

    public static void main(String[] args) {

        // the ultimate superclass Object.  It has 4 methods
        Object a = new Object();
        Object z = new Object();
        System.out.println(a);
        System.out.println(z);
        a.getClass();
        a.toString();
        a.hashCode();
        a.equals(z);
        System.out.println(a);
        System.out.println();

        // Object a is changed to a Shape
        //a= new Shape();
        //System.out.println(a);
        //System.out.println("-----------------------");

        // A new shape b
        //Shape b = new Shape(true, "red");
        //System.out.println(b);
        //System.out.println("-----------------------");

        // A new parallelogram c
        //Parallelogram c = new Parallelogram(true, "blue", 5, 9);
        //System.out.println(c);
        //System.out.println("-----------------------");

        // A new parallelogram d
        //Parallelogram d = new Parallelogram(true, "yellow", 6,8);  // Note that although we assigned a color of yellow,
                                                                    // the constructor made it white since it is not filled
        //System.out.println(d);
        //System.out.println("-----------------------");

        // A new parallelogram made from the Object superclass
        //Object e = new Parallelogram(true, "red", 1,1);
        //System.out.println(e);
        //System.out.println("-----------------------");

        //e = a;  // Change "Object e" to "Shape e" and note that "a" cannot be assigned to "e" because "e" is subclass of "a"
        //System.out.println(e);
        //System.out.println("-----------------------");
        //a = null;
        //System.out.println(a);
        //System.out.println();

        //Parallelogram x = new Parallelogram();
        //System.out.println(x);


    }

}
class Shape{
    private boolean filled;
    private String color;

    public Shape(){
        System.out.println("I am a shape");
        color = "white";
    }
    public Shape(boolean f, String c){
        filled = f;
        if (filled)
            color = c;
        else
            color= "white";

        System.out.println("I am a shape");
    }
    @Override
    public String toString(){
        String message;
        if (filled == false)
            message = "is not filled. The background is "+white;
        else
            message = "is filled with "+ color;
        return "The shape "+ message;
    }

}class Parallelogram extends Shape{
    int height;
    int width;

    public Parallelogram(){
        System.out.println("I am a parallelogram");
    }

    public Parallelogram(boolean f, String c, int h, int w){
        super(f,c);
        height = h;
        width = w;
        System.out.println("I am a parallelogram");
    }
    @Override
    public String toString(){
        return super.toString()+"\n The parallelogram has height of "+height + " and width of "+ width;
    }
}