How to auto-resize the image icon to fit form in Java

in Swing you can add any JComponent to the another JComponent, for Image is JLabel the bestJComponent, then why not put the JLabel#setIcon() to the JButton

 

import java.awt.*;
import javax.swing.*;

public class ResizeIconInButton extends JFrame {
    private static final long serialVersionUID = 1L;

    public ResizeIconInButton() {
        JButton myButton = new JButton();
        myButton.setLayout(new BorderLayout());
        myButton.add(new CustomComponents0());
        add(myButton, BorderLayout.CENTER);
        setPreferredSize(getPreferredSize());
        setTitle("Resize Icon In Button");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        pack();
        setVisible(true);
    }

    public static void main(String[] args) {
        Runnable r = new Runnable() {

            @Override
            public void run() {
                ResizeIconInButton main = new ResizeIconInButton();

            }
        };
        javax.swing.SwingUtilities.invokeLater(r);
    }
}

class CustomComponents0 extends JLabel {

    private static final long serialVersionUID = 1L;

    @Override
    public Dimension getMinimumSize() {
        return new Dimension(200, 100);
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(300, 200);
    }    @Override
    public void paintComponent(Graphics g) {
        int margin = 10;
        Dimension dim = getSize();
        super.paintComponent(g);
        g.setColor(Color.red);
        g.fillRect(margin, margin, dim.width - margin * 2, dim.height - margin * 2);
    }
}