According to this article:
OS X (The operating system run on Macs).
I'm looking forward to seeing it, however being a developer who mostly works in Java and seeing that Apple has a decidedly poor attitude when it comes to Java, I'm very concerned that I will not be able to use the new OS or buy a new Mac for the two years it will take them to update the Java virtual machine for the operating system.
If we're lucky the old JVM will work just as well and we won't have a problem, however I am not confident that they will give it any priority.
This is unfortunate because all the best Java developers I know are now running Macs.
If they just don't do it and I have to update my machine (as a professional tool, I tend to replace my hardware every 1 to 2 years), I just might end up running Linux or FreeBSD instead.
I'd make a plea for Apple to pay attention to their consumers, but they usually don't and I doubt they would listen to me.