Erone method to build the square root of a given number

square_root.java

import javax.swing.JOptionPane;

public class SquareRoot {

	private int attempts=0;
	private double x=0,epsilon = 0;
	
	public SquareRoot(int x,double epsilon,int attempts)
	{
		this.x=(double)x;
		this.epsilon=epsilon;
		this.attempts=attempts;
	}
	public void run()
	{
		int tot_attempts=attempts;
		double x_n = Math.random()*x;
		double x_n_1 = 0;
		while(attempts--  >0 && Math.abs(x_n-x_n_1)>epsilon)
		{
			x_n_1 = x_n;
			x_n = 0.5 * (x_n_1 + x/x_n_1);
		}
		JOptionPane.showMessageDialog(null, "Square root of "+x+" = "+x_n+"\n"+"# Attempts = "+(tot_attempts-attempts),"Result",  JOptionPane.INFORMATION_MESSAGE);
	}
	public static void main(String[] args) {
		int a = Integer.valueOf(JOptionPane.showInputDialog("Inserire il numero"));
		double e = Double.valueOf(JOptionPane.showInputDialog("Distanza dalla valore radice"));
		int t = Integer.valueOf(JOptionPane.showInputDialog("Numero di tentativi"));
		new SquareRoot(a, e, t).run();
	}
}