Here you can find the source of displayInDialog(JComponent comp, JDialog result)
public static JDialog displayInDialog(JComponent comp, JDialog result)
//package com.java2s; /*/* w w w . ja v a 2 s .com*/ Strandz LGPL - an API that matches the user to the data. Copyright (C) 2007 Chris Murphy Strandz LGPL is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA The authors can be contacted via www.strandz.org */ import javax.swing.JComponent; import javax.swing.JDialog; import java.awt.*; public class Main { public static void displayInDialog(JComponent comp) { JDialog dialog = new JDialog((Frame) null, false); displayInDialog(comp, dialog); } public static JDialog displayInDialog(JComponent comp, JDialog result) { Dimension preferredSize = comp.getPreferredSize(); result.setContentPane(comp); result.pack(); Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize(); result.setLocation(screenSize.width / 2 - preferredSize.width / 2, screenSize.height / 2 - preferredSize.height / 2); result.setVisible(true); return result; } }