Also Thomy, I am not sure if you have this implemented or not. but if you want to check it out it couldn't hurt

http://zeroturnaround.com/software/jrebel/

If you where to implement jrebel it would allow you to update the server without having to restart it

Not really a bug... this feature is called z-buffering.

Moreover, jrebel is only supposed to be for the development phase! Using it on a live version would be a bad idea because it decreases performance by a lot. (We're using it for development already for years tho)