The above is a free NetBeans Platform application that you can find here:
Download the sources (or the binaries, which are available there too) from there and then open your app in NetBeans IDE:
Then simply run it (no need to set up anything at all) and you'll have the invoice manager deployed, on the NetBeans Platform.
Nice example for if you want to do something similar.
Thanks Ingmar Hendriks from Amsterdam, who has a bunch of apps on the NetBeans Platform!