Simple gui program ( Add custom drawing surface )

import javax.swing.SwingUtilities;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.BorderFactory;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
 
public class SwingPaintDemo2 {
 
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI(); 
            }
        });
    }
 
    private static void createAndShowGUI() {
        System.out.println("Created GUI on EDT? "+
        SwingUtilities.isEventDispatchThread());
        JFrame f = new JFrame("Swing Paint Demo");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(new MyPanel());
        f.pack();
        f.setVisible(true);
    }
}
 
class MyPanel extends JPanel {
 
    public MyPanel() {
        setBorder(BorderFactory.createLineBorder(Color.black));
    }
 
    public Dimension getPreferredSize() {
        return new Dimension(250,200);
    }
 
    public void paintComponent(Graphics g) {
        super.paintComponent(g);       
 
        // Draw Text
        g.drawString("This is my custom Panel!",10,20);
    }  
}