I can't believe this is not a top comment anymore.

I don't have enough experience with Ruby to comment about it, but as far as Java is concerned, people (myself included) are still complaining it is slooooooooo... <let me pause a bit to collect garbage>... ooow. Don't get me wrong, Java is an excellent language which has plenty of other benefits (as I guess Ruby does too), but raw performance is not one of them.