JAVA Interview Questions

import java.awt.*;
import javax.swing.*;

public class MainForm extends JFrame
{
  public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
          public void run() {
              // Get the size of our screen
              Dimension screenSize =
                  Toolkit.getDefaultToolkit().getScreenSize();

              MainForm mainForm = new MainForm();
              mainForm.setDefaultCloseOperation(
                  JFrame.EXIT_ON_CLOSE);
            
              mainForm.setSize(250, 250);

              // Calculates the position where the MainForm
              // should be paced on the screen.
              mainForm.setLocation((screenSize.width -
                  mainForm.getWidth()) / 2,
                  (screenSize.height -
                  mainForm.getHeight()) / 2);

              mainForm.pack();
              mainForm.setVisible(true);
          }
      });
  }  
}