Java tutorial
//package com.java2s; import java.awt.Component; import java.awt.Dimension; import java.awt.Point; import java.awt.Toolkit; public class Main { public static final double HALF = 2.0; public static void centralizeComponent(Component component, Component otherComponent) { Dimension othersDimension = null; Point othersLocation = null; if (otherComponent == null || !otherComponent.isVisible()) { othersDimension = Toolkit.getDefaultToolkit().getScreenSize(); othersLocation = new Point(0, 0); } else { othersDimension = otherComponent.getSize(); othersLocation = otherComponent.getLocation(); } Point centerPoint = new Point( (int) Math.round(othersDimension.width / HALF - component.getWidth() / HALF) + othersLocation.x, (int) Math.round(othersDimension.height / HALF - component.getHeight() / HALF) + othersLocation.y); component.setLocation(centerPoint); } }