Securing a client-side Java application

Recently I've been developing a client-side Java Swing application for a client, and I've had a creeping concern that at any given time the client could simply take a snapshot build of the system and run-off with it.

The app needs to be connected to the internet in order to do anything, and I was hoping on getting some tips on how I could put some sort of security in-place to prevent the system from working if I wanted to i.e. he may copy/install the application somewhere else without me knowing about it (edit from the comment here).

I'd need this to be fairly transparent to th开发者_C百科e client, and it wouldn't need to be 100% robust as the client is not technically competent and is unlikely to try to 'crack' any security that is there.

Any tips would be much appreciated!

Thanks

I think you're going to want to look into code obfuscation:

http://www.cs.arizona.edu/~collberg/Research/Students/DouglasLow/obfuscation.html

http://java-source.net/open-source/obfuscators