Java Swing - 如何将背景图像添加到JTextArea

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.Image;

import javax.swing.GrayFilter;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

public class Main {
  public static void main(String args[]) {
    JFrame frame = new JFrame("Background Example");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    final ImageIcon imageIcon = new ImageIcon("draft.gif");
    JTextArea textArea = new JTextArea() {
      Image image = imageIcon.getImage();

      Image grayImage = GrayFilter.createDisabledImage(image);
      {
        setOpaque(false);
      }

      public void paint(Graphics g) {
        g.drawImage(grayImage, 0, 0, this);
        super.paint(g);
      }
    };
    JScrollPane scrollPane = new JScrollPane(textArea);
    Container content = frame.getContentPane();
    content.add(scrollPane, BorderLayout.CENTER);
    frame.setSize(250, 250);
    frame.setVisible(true);
  }
}