Java tutorial
//package com.java2s; //License from project: Open Source License import java.awt.GraphicsEnvironment; import java.awt.Point; import java.awt.Window; public class Main { public static void centerWindow(Window w) { Point center = GraphicsEnvironment.getLocalGraphicsEnvironment().getCenterPoint(); centerWindow(w, center); } public static void centerWindow(Window w, Window reference) { Point refCorner = reference.getLocation(); Point center = new Point(refCorner.x + reference.getWidth() / 2, refCorner.y + reference.getHeight() / 2); centerWindow(w, center); } private static void centerWindow(Window w, Point center) { int x = center.x - w.getWidth() / 2; int y = center.y - w.getHeight() / 2; w.setLocation(x, y); } }