There's been a lot said about closures both in favor and against the last couple of years. The debate has raged on for what feels like an eternity. But the semi-official announcement at Devoxxx recently that closures won't be making it into java7 seems to have put everyone back on their heels a bit. I, for one, am relieved at the announcement. Others are not so thrilled and have gone so far as to declare that Java is dead for their lack. Personally, every major proposal out there made my eyes bleed. There were so many gymnastics being proposed to deal with typing and generics and backward compatibility and the like that most of those proposals just made a mangle of the language. I did see one idea that I like (my thoughts on that here) but there's little chance it'll get any serious traction.
I've used closures in both my fan work and my groovy work and I've enjoyed using them. But the syntax employed is much simpler than what the main proposals had offered. As nice as closures are, inner classes have served me well enough so far with very little heartburn. Until Sun is ready to break with older versions of Java, I'm just not sure how well closures will work the current language and VM constraints.
What I was happiest too see was Mark Reinhold's jigsaw project. A small, modular, independently updatable runtime would be fantastic. I know many are upset at the lack of any major language changes being promised in java7 but I'd rather see what we have now work better. Let's not destroy the language trying to shoehorn in things that just aren't working out.