How can I calculate distance between multiple latitude and longitude?

Question

I want to calculate total distance between each points both contains lat and long, these points are stored in local database, so the scenario is I want to calculate distance fro

Answer 1

class DistanceCalculator
{
    public static void main (String[] args) throws java.lang.Exception
    {
        System.out.println(distance(32.9697, -96.80322, 29.46786, -98.53506, "M") + " Miles\n");
        System.out.println(distance(32.9697, -96.80322, 29.46786, -98.53506, "K") + " Kilometers\n");
        System.out.println(distance(32.9697, -96.80322, 29.46786, -98.53506, "N") + " Nautical Miles\n");
    }

    private static double distance(double lat1, double lon1, double lat2, double lon2, String unit) {
        if ((lat1 == lat2) && (lon1 == lon2)) {
            return 0;
        }
        else {
            double theta = lon1 - lon2;
            double dist = Math.sin(Math.toRadians(lat1)) * Math.sin(Math.toRadians(lat2)) + Math.cos(Math.toRadians(lat1)) * Math.cos(Math.toRadians(lat2)) * Math.cos(Math.toRadians(theta));
            dist = Math.acos(dist);
            dist = Math.toDegrees(dist);
            dist = dist * 60 * 1.1515;
            if (unit == "K") {
                dist = dist * 1.609344;
            } else if (unit == "N") {
                dist = dist * 0.8684;
            }
            return (dist);
        }
    }
}