Round Decimal Number Into 2 Decimal

Here is my code and i want to convert number into 2 decimal but this code not give me result how to check my code.

import javax.swing.JOptionPane;
public class showtime{
public static void main(String[] args){
double total_mili=System.currentTimeMillis();
JOptionPane.showMessageDialog(null,total_mili, "Total milisecond",JOptionPane.INFORMATION_MESSAGE);
double seconds=total_mili/60;
double sec=(double)(seconds * 100) / 100.000;
JOptionPane.showMessageDialog(null,seconds, "Total Second",JOptionPane.INFORMATION_MESSAGE);
JOptionPane.showMessageDialog(null,sec, "Total Second",JOptionPane.ERROR_MESSAGE);
}
}