/home/wpollock1/public_html/Java/ModuleDemo/Hello9.java

/*  Steps to create a Java 9 module:
    mkdir Java9HelloWorld
    cd Java9HelloWorld
    mkdir mods src mlib mods/foo src/foo
    (You can put all modules in a single mods directory, and all modular jars
    in a single mlib directory, but you will need a separate src directory
    for each module.)

    notepad src/foo/Hello9.java src/module-info.java

    The src\module-info.java file has this content:
        module mymod {
            requires java.desktop;  // Module containing javax.swing.
        }

    javac -d mods\mymod src\module-info.java src\foo\Hello9.java
    java -p mods -m mymod/foo.Hello9
    Hello, Java 9 world!

    To package in a jar:
    jar -cfe mlib\mymod.jar foo.Hello9 -C mods\mymod .
    java -p mlib -m mymod
    Hello, Java 9 world!
    (Running "java -jar mymod.jar" also works.)
    Double-click mymod.jar should show the message in a dialog window.

    tree output:
        .
        ├───mlib
        │       mymod.jar
        │
        ├───mods
        │   └───mymod
        │       │   module-info.class
        │       │
        │       └───foo
        │               Hello9.class
        │
        └───src
            │   module-info.java
            │
            └───foo
                    Hello9.java
*/

// Java 9 Hello World module sample.  This simple program displays a
// friendly message, to the console if started from the console, or with
// a JOptionPane dialog window, if double-clicked.
//
// Written 11/2017 by Wayne Pollock, Tampa Florida USA

package foo;

import javax.swing.JOptionPane;

public class Hello9 {
    public static void main ( String[] args ) {
        if ( System.console() != null )
            System.out.println( "Hello, Java 9 world!" );
        else
            JOptionPane.showMessageDialog( null, "Hello, Java 9 world!" );
    }
}