hey guys, i am working with java program. so i did some sub and super classes and just start learning abstract classes. in this project im building my program as given from UML diagram. i do have shape.java also Circle.java, Rectangle.java as well as main class ShapeClient.java. all those classes are working. but right now i am trying to add Triangle.java which will not calculate area but will print true or false if sides are equal or not so i am using isEquilateral method. i have Triangle.java and it compiles and it is abstract class. however when i am trying to use it in the ShapeClient.java i have error //ShapeClient.java:14: error: Triangle is abstract; cannot be instantiated Shape s3 = new Triangle("Triangle 3", 10, 10, 10);

so that is where i am stuck. i will put my classess what i have.

shape.java

public abstract class Shape { private String name;

public Shape(String name) { this.name = name; }

public abstract double getArea();

//public abstract boolean isEquilateral();

public String getName() { return name; } }

Circle.java

public class Circle extends Shape {

private double radius;

public Circle(String name, double radius) {

super(name);

this.radius = radius;

}

public double getArea() {

return Math.PI * radius * radius;

}

}

rectangle.java

public class Rectangle extends Shape {

private double width;

private double length;

public Rectangle(String name, double width, double length) {

super(name);

this.width = width;

this.length = length;

}

public double getArea() {

return width * length;

}

}

Triangle.java

public abstract class Triangle extends Shape{

private double size1;

private double size2;

private double size3;

public Triangle(String name, double size1,

double size2,double size3) {

super(name);

this.size1 = size1;

this.size1 = size2;

this.size1 = size3;

}

public boolean isEquilateral(){

if(size1==size2 & size2==size3){

}

return true;

}

}

ShapeClient //main program

import java.util.ArrayList;

public class ShapeClient

{

public static void main(String[] args) {

ArrayList shapeList = new ArrayList();

Shape s1 = new Circle("circle 1", 10);

shapeList.add(s1);

Shape s2 = new Rectangle("rectangle 2", 100, 100);

shapeList.add(s2);

Shape s3 = new Triangle("Triangle 3", 10, 10, 10);

shapeList.add(s3); //this is where i am stuck

System.out.println("triangle is isEquilateral");

if (!s1.getClass().isInstance(s2)) {

System.out.println("Actual types of s1 and s2 are different");

}

double totalArea = sumAreasOfShapes(shapeList);

System.out.println("The total area of the shapes are " + totalArea);

}

public static double sumAreasOfShapes(ArrayList shapeList) {

double sum = 0.;

// Use the for loop

for (int i=0; i

sum += shapeList.get(i).getArea();

}

return sum;

}

}

need help to make program work Thanks.

Shape + getArea(): double Triangle Rectangle Circle + isEquilateral(): boolean getArea(): doublegetArea(): double