把下面g.drawImage(image,0,0,this);和super.paint(g)；两行代码位置互换，会出现文本域不能输入编辑，为什么？

public class BackgroundJTextArea extends JTextArea {

    private Image image;

    public BackgroundJTextArea(String path) {

        ImageIcon imageIcon = new ImageIcon(path);

        image = imageIcon.getImage();

        setOpaque(false);

    }

    @Override

    public void paint(Graphics g) {

        g.drawImage(image, 0, 0, this);//这里

        super.paint(g);//这里

    }

}

///////

public class BackgroundJTextAreaTest extends JFrame {

private JPanel contentPane;

public static void main(String[] args) {

BackgroundJTextAreaTest frame = new BackgroundJTextAreaTest();

frame.setVisible(true);

}

public BackgroundJTextAreaTest() {

setTitle("为文本域设置背景图片");

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

setBounds(100, 100, 450, 300);

contentPane = new JPanel();

contentPane.setLayout(new BorderLayout(0, 0));

setContentPane(contentPane);

JScrollPane scrollPane = new JScrollPane();

contentPane.add(scrollPane, BorderLayout.CENTER);

JTextArea textArea = new BackgroundJTextArea("src/b.jpg");

textArea.setLineWrap(true);

textArea.setFont(new Font("微软雅黑", Font.PLAIN, 16));

scrollPane.setViewportView(textArea);

}

}