Convert swing component to image

package y11.m03;

import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSpinner;
import javax.swing.JTextField;

public class PrintTester {

    public static void main(String[] args) throws IOException {
        JPanel p = new JPanel(new GridLayout(2, 2));
        p.add(new JTextField("wwww", 20));
        p.add(new JLabel("dfdfdf"));
        p.add(new JSpinner());
        p.add(new JButton("fdfdf"));

        BufferedImage image = createImage(p);
        ImageIO.write(image, "png", new File("PrintTest2.png"));
    }

    // if component is rendered
    public static BufferedImage createImage(JComponent component) {
        int w = component.getWidth();
        int h = component.getHeight();
        BufferedImage img = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        Graphics2D g = img.createGraphics();
        component.paint(g);
        return img;
    }

    // if component is not rendered
    public static BufferedImage createImage(JComponent component, AffineTransform transform) throws IOException, ClassNotFoundException {
        if (component == null)
            return null;
        JFrame f = new JFrame(); // for paint
        JComponent clone = (JComponent) clone(component);
        f.add(clone);
        f.pack();

        BufferedImage image = new BufferedImage(clone.getWidth(), clone.getHeight(), BufferedImage.TYPE_INT_ARGB);
        Graphics2D g = image.createGraphics();
        if (transform != null)
            g.setTransform(transform);
        clone.paint(g);
        f.dispose();
        return image;
    }

    public static <T extends Serializable> T clone(T source) throws IOException, ClassNotFoundException {
        Object newObject = new Object();
        ObjectOutputStream ooStr = null;
        ByteArrayOutputStream baoStr = new ByteArrayOutputStream();
        ooStr = new ObjectOutputStream(baoStr);
        ooStr.writeObject(source);
        ooStr.flush();
        ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(baoStr.toByteArray()));
        newObject = in.readObject();
        ooStr.close();
        return (T) newObject;
    }
}