JSFDays 2009
Aus Java Student User Group Austria - Java + JVM in Wien Österreich / Vienna Austria
This reminds me of a piece of sowrafte I stumbled upon earlier this year. Basically, you put it into my code and you yourself have your own kill-switch basically. This way if your client will not pay, you can make every single copy of your program stop working. If you were a client, would you be okay with this? Knowing that you are in fact going to pay and everything?
