Sets the type of Window decorations (such as borders, widgets for
 closing a Window, title ...) the JRootPane should
 provide. The default is to provide no Window decorations
 (NONE).
 
This is only a hint, and some look and feels may not support this. This is a bound property.
windowDecorationStyle | Constant identifying Window decorations to provide. | 
IllegalArgumentException |  if style is
        not one of: NONE, FRAME,
        PLAIN_DIALOG, INFORMATION_DIALOG,
        ERROR_DIALOG, COLOR_CHOOSER_DIALOG,
        FILE_CHOOSER_DIALOG, QUESTION_DIALOG, or
        WARNING_DIALOG. | 
JDialog.setDefaultLookAndFeelDecorated, JFrame.setDefaultLookAndFeelDecorated, LookAndFeel.getSupportsWindowDecorations
Diagram: RootPaneContainer