Add icon to a tab in JTabbedPane in Java

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Graphics;
//from  w ww . j  a va  2  s  .co  m
import javax.swing.Icon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTabbedPane;

public class Main extends JFrame {
  public static void main(String[] args) {
    Main that = new Main();
    that.setVisible(true);
  }

  public Main() {
    setSize(450, 350);
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    JTabbedPane tabbedPane = new JTabbedPane();

    tabbedPane.addTab("Button", 
        new TabIcon(), 
        new JButton(""), 
        "Click here for Button demo"); 
    
    getContentPane().add(tabbedPane, BorderLayout.CENTER);
  }
}
class TabIcon implements Icon {
  public int getIconWidth() {
    return 16;
  }

  public int getIconHeight() {
    return 16;
  }

  public void paintIcon(Component c, Graphics g, int x, int y) {
    g.setColor(Color.black);
    g.fillRect(x + 4, y + 4, getIconWidth() - 8, getIconHeight() - 8);
    g.setColor(Color.cyan);
    g.fillRect(x + 6, y + 6, getIconWidth() - 12, getIconHeight() - 12);
  }
}