Calculate the distance between 2 points

HaversineDistance.java

/**
 * This is the implementation Haversine Distance Algorithm between two places
 * @author ananth
 *  R = earth’s radius (mean radius = 6,371km)
    Δlat = lat2− lat1
    Δlong = long2− long1
    a = sin²(Δlat/2) + cos(lat1).cos(lat2).sin²(Δlong/2)
    c = 2.atan2(√a, √(1−a))
    d = R.c
 *
 */
 
public class HaversineDistance {
 
    /**
     * @param args
     * arg 1- latitude 1
     * arg 2 - latitude 2
     * arg 3 - longitude 1
     * arg 4 - longitude 2
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        final int R = 6371; // Radious of the earth
        Double lat1 = Double.parseDouble(args[0]);
        Double lon1 = Double.parseDouble(args[1]);
        Double lat2 = Double.parseDouble(args[2]);
        Double lon2 = Double.parseDouble(args[3]);
        Double latDistance = toRad(lat2-lat1);
        Double lonDistance = toRad(lon2-lon1);
        Double a = Math.sin(latDistance / 2) * Math.sin(latDistance / 2) + 
                   Math.cos(toRad(lat1)) * Math.cos(toRad(lat2)) * 
                   Math.sin(lonDistance / 2) * Math.sin(lonDistance / 2);
        Double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
        Double distance = R * c;
         
        System.out.println("The distance between two lat and long is::" + distance);
 
    }
     
    private static Double toRad(Double value) {
        return value * Math.PI / 180;
    }
 
}