Java Tutorial/Development/Toolkit

Centering a Frame, Window, or Dialog on the Screen

import java.awt.Dimension;
import java.awt.Toolkit;
import javax.swing.JFrame;
public class Main {
  public static void main(String[] argv) throws Exception {
    Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
    JFrame window = new JFrame();
    window.setSize(300,300);
    
    int w = window.getSize().width;
    int h = window.getSize().height;
    int x = (dim.width - w) / 2;
    int y = (dim.height - h) / 2;
    window.setLocation(x, y);
    window.setVisible(true);
  }
}

Getting the Screen Size

import java.awt.Dimension;
import java.awt.Toolkit;
public class Main {
  public static void main(String[] argv) throws Exception {
    Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
    System.out.println(dim);
  }
}

java.awt.Toolkit

The Toolkit abstract class has the following methods:

1. public static Toolkit getDefaultToolkit(): Returns the default implementation of the Toolkit class.
2. public abstract void beep (): Produces a beep sound.
3. public abstract Dimension getScreenSize (): Returns a java.awt.Dimension object containing the width and the height of the screen.