Calculating distance between two points, using latitude longitude?

I am trying to calculate distance between two points using java code, I have written a code but it is not working. I have checked various forums to get the resolution to my query. I have found java questions and answers specifically posted on this forum and hope I'll get a solution from the member of this community.

Here is code

final double RADIUS = 6371.01;
double temp = Math.cos(Math.toRadians(latA))
            * Math.cos(Math.toRadians(latB))
            * Math.cos(Math.toRadians((latB) - (latA)))
            + Math.sin(Math.toRadians(latA))
            * Math.sin(Math.toRadians(latB));
    return temp * RADIUS * Math.PI / 180;