If by startups you mean those website with strange names that usually end in -ly or -ify than the "big thing" is RoR. Other way I am not 100% sure. I think that

If by startups you mean those website with strange names that usually end in -ly or -ify than the "big thing" is RoR. Other way I am not 100% sure. I think that if I needed to choose I would not go for Java for the web. But I too would love to hear the opinion of someone more experienced.