JComponent - cannot set Background/Border

I want to add a JComponent in my basic JFrame. My problem is that I cannot set background color or border for my component.

JFrame

JPanel drawPanel = new JPanel(new GridBagLayout());
drawPanel.add(new DrawingBoard());
JScrollPane scrollPane = new JScrollPane(drawPanel);
this.add(scrollPane, BorderLayout.CENTER);
this.setVisible(true);

JComponent

private class DrawingBoard extends JComponent {
        ...
        public DrawingBoard() {
        this.setPreferredSize(new Dimension(500, 500));
        this.setBackground(Color.WHITE);     //doesn't work
        this.setBorder(BorderFactory.createEmptyBorder(0,10,10,10)); //doesn't work
        this.setOpaque(true);
        ...

I found a simple solution to my problem. I just added the Jcomponent to a Jpanel and then I added the Jpanel to the Jframe.

    JPanel outer = new JPanel(new GridBagLayout()); 
    JPanel drawPanel = new JPanel(new GridBagLayout());
    drawPanel.add(new DrawingBoard(500,500));
    drawPanel.setBackground(Color.WHITE);
    outer.setBorder(BorderFactory.createEmptyBorder(0,10,10,10));
    JScrollPane scrollPane = new JScrollPane(drawPanel);
    outer.add(scrollPane);
    this.add(outer, BorderLayout.CENTER);