Program

public class Test {

    public static void main(String[] args) {
        Triangle triangle = new Triangle();
        Circle circle = new Circle();
        Rectangle rectangle = new Rectangle();

        triangle.getSide1();
        triangle.getSide2();
        triangle.getSide3();
        triangle.setSide1(1.0);
        triangle.setSide2(2.0);
        triangle.setSide3(3.0);
        triangle.getArea();
        triangle.getPerimeter();
        triangle.getColor();
        triangle.setColor("Yellow");
        triangle.getFilled();
        triangle.setFilled(true);
        System.out.println(triangle);

        circle.getRadius();
        circle.setRadius(5);
        circle.getArea();
        circle.getPerimeter();
        circle.getDiameter();
        circle.getColor();
        circle.setColor("Green");
        circle.getFilled();
        circle.setFilled(false);
        System.out.println(circle);

        rectangle.getLength();
        rectangle.setLength(10);
        rectangle.getWidth();
        rectangle.setWidth(10);
        rectangle.getArea();
        rectangle.getPerimeter();
        rectangle.getColor();
        rectangle.setColor("Red");
        rectangle.getFilled();
        rectangle.setFilled(true);
        System.out.println(rectangle);
    }

}


public class GeometricObject {
    private String color;
    private boolean filled;

    public GeometricObject() {
        color = "";
        filled = true;
    }

    public String getColor() {
        return color;
    }

    public void setColor(String color) {
        this.color = color;
    }

    public boolean getFilled() {
        return filled;

    }

    public void setFilled(boolean filled) {
        this.filled = filled;
    }

    @Override
    public String toString() {
        return "The object's color is: " + color + ". Is the object filled?" + filled;
    }

}

public class Triangle extends GeometricObject {
    private double side1 = 2.0;
    private double side2 = 2.0;
    private double side3 = 2.0;

    public Triangle (double side1, double side2, double side3){
        super();
        this.side1=side1;
        this.side2=side2;
        this.side3=side3;

    }

    public double getSide1() {
        return side1;
    }

    public void setSide1(double side1) {
        this.side1 = side1;
    }

    public double getSide2() {
        return side2;
    }

    public void setSide2(double side2) {
        this.side2 = side2;
    }

    public double getSide3() {
        return side3;
    }

    public void setSide3(double side3) {
        this.side3 = side3;
    }

    public double getArea( double side1, double side2, double side3){
        double s = (side1+side2+side3)/2;
        return Math.sqrt(s*(s-side1)*(s-side2)*(s-side3));
    }

    public double getPerimeter(){
        return side1+side2+side3;
    }


    public String toString(double side1, double side2, double side3){
        return super.toString() + "Triangle: side1 = " + side1 +
                " side2 = " + side2 + " side3 = " + side3 + "Area is:" + this.getArea() +
                "Perimeter is: " +this.getPerimeter();

    }


}


public class Circle extends GeometricObject{
    private double radius;

    public Circle(double radius) {
    super ();
    this.radius=radius;
    }

    public double getRadius() {
        return radius;
    }

    public void setRadius(double radius) {
        this.radius = radius;
    }

    public double getArea() {
        return Math.pow(radius, 2) * Math.PI;

    }

    public double getPerimeter(){
        return 2* Math.PI * radius;
    }

    public double getDiameter(){
        return 2* radius;
    }


    public String toString(double radius){
        return super.toString() + "Radius is: " +radius+ ". Area is: " +this.getArea()
        + ". Perimeter is: " +getPerimeter()+ ". Diameter is: " +getDiameter();
    }
}


public class Rectangle extends GeometricObject{
    private double width;
    private double length;

    public Rectangle(double width, double length) {
        super();
        this.length=length;
        this.width=width;
    }

    public double getWidth() {
        return width;
    }

    public void setWidth(double width) {
        this.width = width;
    }

    public double getLength() {
        return length;
    }

    public void setLength(double length) {
        this.length = length;
    }

    public double getArea(){
        return length * width;
    }

    public double getPerimeter(){
        return (length*2) + (width*2);
    }

    public String toString(double length, double width){
        return super.toString() + "Perimeter is: " +getPerimeter() +
                ". Area is: " +getArea();
    }
}