import javax.swing.JOptionPane;
public class while_num {

public static void main(String[] args) {

String parar="S";

int cont=0;
while (parar=="S")
{
JOptionPane.showMessageDialog (null,"Numero: " +cont);
cont=cont+1;

parar=JOptionPane.showInputDialog ("¿Quiere continuar 1 si no 2?");

}
}
}