import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;

import javax.swing.JButton;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class Main {

public static void main(String[] args) {
try {
paintToJpeg();
} catch (Exception e) {
e.printStackTrace();
}
}

private static void paintToJpeg() throws IOException {
BufferedImage image= new BufferedImage(200,100, BufferedImage.TYPE_INT_RGB);
Graphics g=image.getGraphics();
OutputStream out = new FileOutputStream("c:/temp/test.jpg");
JButton button = new JButton("Test");
button.setSize(200, 100);
button.paint(g);
JPEGImageEncoder encoder= JPEGCodec.createJPEGEncoder(out);
encoder.encode(image);
out.close();
}
}