Java Fullscreen JFrame
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
Rubahn Die U-Bahn
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);GraphicsEnvironment graphics =
GraphicsEnvironment.getLocalGraphicsEnvironment();
GraphicsDevice device = graphics.getDefaultScreenDevice();
JFrame frame = new JFrame("Fullscreen");
device.setFullScreenWindow(frame);