Java tutorial
//package com.java2s; import java.awt.Dimension; import java.awt.Point; import javax.swing.JDialog; import javax.swing.JFrame; public class Main { public static void setCenterOfParent(JFrame parent, JDialog dialog) { Point parentPosition = parent.getLocation(); Dimension parentSize = parent.getSize(); Dimension size = dialog.getSize(); Point position = new Point(parentPosition.x + (parentSize.width / 2 - size.width / 2), parentPosition.y + (parentSize.height / 2 - size.height / 2)); dialog.setLocation(position); } public static void setCenterOfParent(JDialog parent, JDialog dialog) { Point parentPosition = parent.getLocation(); Dimension parentSize = parent.getSize(); Dimension size = dialog.getSize(); Point position = new Point(parentPosition.x + (parentSize.width / 2 - size.width / 2), parentPosition.y + (parentSize.height / 2 - size.height / 2)); dialog.setLocation(position); } }