Thankyou Tom for your reply to my first post on this site.
Apologies for not using CodeTags, you are right, it would have made the code a lot easier to read and digest.
I've changed the code as you have suggested, in order to instantiate an object for the inner class and this works fine!
Actually the reason I initially did this is because I have been watching CBTNugget videos for the
SCJP exam. The videos are actually quite old (created in 2004) for
Java 1.4. The videos actually show this (import Invoice.*; code) and the code compiling, which was why I was a little confused as to why this wasn't working on my machine, using Java 1.6.
Maybe this was possible in Java 1.4??
Anyhow thankyou Tom and also thankyou Campbell.