Triangle Area

/* Write a program that enters 3 points in the plane (as integer x and y coordinates),
 * calculates and prints the area of the triangle composed by these 3 points.
 * Round the result to a whole number.
 * In case the three points do not form a triangle, print "0" as result. */

import java.util.Locale;
import java.util.Scanner;

public class _02_TriangleArea {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Locale.setDefault(Locale.ROOT);
        Scanner scan = new Scanner(System.in);
        System.out.println("You must enters 3 points of the plane (x, y), which formed a Triangle!");

                // Here will using defined class Point:
        Point[] threePoints = new Point[3];
        for (int point = 0; point < threePoints.length; point++) {
            System.out.print("Enter next Point (2 Integer numbers for X and Y): ");
            double x = scan.nextInt();
            double y = scan.nextInt();
            threePoints[point] = new Point(x, y);
        }

        boolean isTriangle = checkGivenThreePointsIsFormTriangle(threePoints);

        long triangleArea = 0;
        if (isTriangle) {
            triangleArea = Math.round(calculateTriangleAreaFromGiven3Points(threePoints));
        }

        System.out.println("The Area of the Triangle with these 3 points is: " + triangleArea);
    }

    private static double calculateTriangleAreaFromGiven3Points(Point[] threePoints) {
        // TODO Auto-generated method stub
        double area = 0;
        for (int i = 0; i < threePoints.length; i++) {
            Point point1 = threePoints[i % 3];
            Point point2 = threePoints[(i + 1) % 3];
            Point point3 = threePoints[(i + 2) % 3];
            area += point1.getX() * (Point.minusY(point2, point3));
        }

        area = Math.abs(area / 2);
        return area;
    }

    private static boolean checkGivenThreePointsIsFormTriangle(
            Point[] threePoints) {
        // TODO Auto-generated method stub
        double[] collinearFactor = new double[2];
        for (int i = 0; i + 1 < threePoints.length; i++) {
            Point currentPoint = threePoints[i];
            Point nextPoint = threePoints[i + 1];
            double diffY = Point.minusY(nextPoint, currentPoint);
            double diffX = Point.minusX(nextPoint, currentPoint);
            collinearFactor[i] = (diffY / diffX);
        }

        if (collinearFactor[1] == collinearFactor[0]) {
            return false;
        }

        return true;
    }

}