Java tutorial
//package com.java2s; import java.awt.*; import javax.swing.JFrame; public class Main { public static void centerFrame(JFrame frame) { GraphicsDevice defaultScreen = GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice(); Rectangle screenSize = defaultScreen.getDefaultConfiguration().getBounds(); int midx = screenSize.width / 2; int midy = screenSize.height / 2; int posx = midx - (frame.getWidth() / 2); int posy = midy - (frame.getHeight() / 2); frame.setLocation(posx, posy); } }