I have been using Windows XP & the latest version of NetBeans to compile
simple Java programs as I am learning the languages.  I just tried to do a
command line compile & execute and I cannot get it to work so I wend back
to the "Hello World" program with the same result.  Here is the program,
the commands I tried, and the error result:

The program file contains:
    class HelloWorldApp {
        public static void main(String[] args) {
                   System.out.println("Hello World!");
        }
    }

The Commands:
  To Compile:     javac k:\HelloWorldApp.java  (This worked)
  To Execute:  java k:\HelloWorldApp (This failed)
  The Result:   
Exception in thread "main" java.lang.NoClassDefFoundError: k:\HelloWorldApp
Caused by: java.lang.ClassNotFoundException: k:\HelloWorldApp
       at java.net.URLClassLoader$1.run(Unknown Source)
       at java.security.AccessController.doPrivileged(Native Method)
       at java.net.URLClassLoader.findClass(Unknown Source)
       at java.lang.ClassLoader.loadClass(Unknown Source)
       at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
       at java.lang.ClassLoader.loadClass(Unknown Source)
       at java.lang.ClassLoader.loadClassInternal(Unknown Source)

I also tried java K:\NonExistantFile which, of course, failed but with
different errors than the above so it must be finding the .class file but
doesn't like something in it.

What am I doing wrong?  Thanks!