Hello World using the JOptionPane

HelloGUI.java

/***********************************************
* HelloGUI.java
* Aaron P. Clark, A. Tres Finocchiaro
***********************************************/

import javax.swing.*;
public class HelloGUI {
    public static void main(String ... args) throws Throwable {
        SwingUtilities.invokeAndWait(() -> JOptionPane.showMessageDialog(null, "Hello, World!"));
    }
}

imprime