===================================================================== JPanel test = new JPanel(); ............ test.setBackground(new Color(255, 0, 0, 255)); //레드test.setBackground(new Color(0, 255, 0, 255)); //그린test.setBackground(new Color(0, 0, 255, 255)); //블루test.setBackground(new Color(255, 0, 0, 0)); //투명 =====================================================================