package messagedialog;import javax.swing.UIManager;import java.awt.*;/** * <p>Title: Message Dialog Demo</p> * <p>Description: This is a MessageDialog demo</p> * <p>Copyright: Copyright (c) 2002</p> * <p>Company: d6-125</p> * @author Liujun * @version 1.0 */public class Application1 {  boolean packFrame = false;  //Construct the application  public Application1() {    MessageDialogFrame frame = new MessageDialogFrame();    //Validate frames that have preset sizes    //Pack frames that have useful preferred size info, e.g. from their layout    if (packFrame) {      frame.pack();    }    else {      frame.validate();    }    //Center the window    Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();    Dimension frameSize = frame.getSize();    if (frameSize.height > screenSize.height) {      frameSize.height = screenSize.height;    }    if (frameSize.width > screenSize.width) {      frameSize.width = screenSize.width;    }    frame.setLocation((screenSize.width - frameSize.width) / 2, (screenSize.height - frameSize.height) / 2);    frame.setVisible(true);  }  //Main method  public static void main(String[] args) {    try {      UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());    }    catch(Exception e) {      e.printStackTrace();    }    new Application1();  }}