JAVA

fullscreen jframe

// For fullscreen, put the following in your code:

frame.setExtendedState(JFrame.MAXIMIZED_BOTH); 

// You can also set the dimensions of the window like this:

frame.setSize(1920, 1080); // Change to resolution of your screen.

jframe full screen

frame.setExtendedState(JFrame.MAXIMIZED_BOTH); 
frame.setUndecorated(true);
frame.setVisible(true);

set jframe fullscreen

GraphicsEnvironment graphics = 
		GraphicsEnvironment.getLocalGraphicsEnvironment();
        
GraphicsDevice device = graphics.getDefaultScreenDevice();
JFrame frame = new JFrame("Fullscreen");
device.setFullScreenWindow(frame);