Use a JPanel bean
as a composition surface for other user interface components, such as
buttons, lists, and text. You can add a panel to a window, an applet,
or another panel. In a Swing window or JApplet, a JPanel can either
serve as the contentPane, or be added to the contentPane.
Adding a pane or panel
Sun's JPanel bean documentation
Pane and panel beans
Beans for visual composition