How to create Java Digital clock using Swing

How to create Java Digital clock using Swing

Below java code will create a Digital Java clock using swing components which include JButton, JFrame etc.

import java.awt.Color;
import java.awt.Font;
import java.text.SimpleDateFormat;
import javax.swing.JButton;
import javax.swing.JFrame;
import java.util.Calendar;
import java.util.Date;
import javax.swing.UIManager;


public class JavaDigitalClock  extends JFrame implements Runnable{
    Thread thread=null;
    int hours=0, minutes=0, seconds=0;
    String timeString = "";
    JButton button;

    JavaDigitalClock()
    {
        super("Java Digital clock Example");
        try{
            UIManager.setLookAndFeel
                    ("com.sun.java.swing.plaf.windows.WindowsClassicLookAndFeel");
        }
        catch(Exception e){e.printStackTrace();}

        button=new JButton();

        thread = new Thread(this);
        thread.start();

        button=new JButton();
        button.setBounds(50,50,00,50);
        button.setBackground(Color.BLACK);
        button.setForeground(Color.WHITE);
        button.setFont(new Font("Times New Roman",Font.BOLD,20));
        add(button);
        setSize(300,400);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(null);
        setVisible(true);

    }

    @Override
    public void run() {
        try {
            while (true) {

                Calendar calendar = Calendar.getInstance();
                hours = calendar.get( Calendar.HOUR_OF_DAY );
                if ( hours > 12 ) hours -= 12;
                minutes = calendar.get( Calendar.MINUTE );
                seconds = calendar.get( Calendar.SECOND );

                SimpleDateFormat formatter = new SimpleDateFormat("hh:mm:ss");
                Date date = calendar.getTime();
                timeString = formatter.format( date );

                showTime();

                thread.sleep( 1000 );  // interval given in milliseconds              }
        }
        catch (Exception e) { }

    }
    public void showTime()
    {
        button.setText(timeString);
    }
    public static void main(String args[])
    {
        new JavaDigitalClock();
    }
}