Iv'e developed Swing for 10 years and I think it's basically botched. Sun had no clue about UI development, and Sing is the expression of that. Compared with the UI frameworks on OS X it's like night and day. But I digress - I think SWT is a much better approach in any case.
From Apple's Mac App Store review guidelines: "Apps that use deprecated or optionally installed technologies (e.g., Java, [PowerPC code requiring] Rosetta) will be rejected."
http://www.appleinsider.com/articles/10/10/20/apple_issues_r...
Java in XCode was already deprecated, but it sounds like there won't even be a (standard) install of the Java runtime in Mac OS X Lion.
It's the Swing apps (such as Netbeans, etc) that are potentially in trouble. Apple has been maintaining their own code for Swing. If they are going to stop maintaining this, I hope they contribute their changes back to OpenJDK so that someone attempting to maintain a Mac version does not have to reimplement this.
I wonder if Apple is really going to stop maintaining their port of Java, or if this move is to be able to say "you can't use Java for App Store for Mac apps because we could possibly stop including it." Or maybe they are planning to hand over development to Oracle.
I don't use any Mac specific APIs except for checking/setting some properties to do things like put the menus in the right place. The rest is straight Swing. So no great loss as long as Oracle provides a good implementation.