[redhead]

Thats actualy a very simple one:

class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello World!");
    }
}

And you'll compile it with

> javac filename.java

Which produces the filename.class file, then you can run it with the

> java filename

If this produces errors like

Exception in thread "main" java.lang.NoClassDefFoundError: HelloWorld

Try executing it with the CLASSPATH argument ie

> java -cp . filename

If that produces errors, please show them as they appear.