It's a new brand of property support, submitted by Remi Forax. Have a look, and let the huge language debates begin...
Personally, I like what he's done, but then again, I'm a fan of properties-as-first-class-citizens support, a la C#. I'm not so wild about introducing the keyword (I like the C# syntax), but I can understand where the C# syntax is deemed a bit cryptic to Java developers. Besides, Remi's done the Right Thing by not making property (or abstract property) an actual keyword, so we don't have accidental backwards incompatibility issues to worry about.
Mind you, I sincerely doubt this is the final form it'll take in Java7, but this is encouraging--people are hacking on the compiler and producing concrete examples of ideas, not just ideas in limbo.
Hats off to you, Remi!