Numerical way to do the square root

Rooting.java

public class Rooting {
	public static void main(String[] args) {
		System.out.println(next(1000, 2));
		System.out.println(Math.sqrt(2));
	}
	
	public static double next(int n, double r) {
		if (n <= 0) return 1;
		
		double xn = next(n - 1, r);
		return 0.5*(xn + r / xn);
	}
}