Java tutorial
import java.awt.Dimension; import java.awt.Toolkit; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import javax.swing.JFrame; public class Main extends JFrame { public Main() { setTitle("CenteredFrame"); addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) { System.exit(0); } }); Toolkit tk = Toolkit.getDefaultToolkit(); Dimension screenSize = tk.getScreenSize(); int screenHeight = screenSize.height; int screenWidth = screenSize.width; setSize(screenWidth / 2, screenHeight / 2); setLocation(screenWidth / 4, screenHeight / 4); } public static void main(String[] args) { JFrame frame = new Main(); frame.setVisible(true); } }