How do I make a centered JFrame?

If you have a JFrame and you want to center the position in the screen you can use the following formula. Let's say you have a class called MainForm.

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); } }); } }