Java for a Ruby/Rails user

I haven't had any time to look at it firsthand but I know of a few
java devs that are pretty happy with GWT or echo2, especially if
you've done any programming in swing. If I were to write a java web
app those would be the first places I'd go and "check out" unless I
just needed something
quick and dirty in which case I'd just bang out some jsp pages.

Here's one of those friends that did a writeup on his process of
looking for a java based webapp framework:

Hope that helps,