Scott Hanselman (the Zen master himself) posted an interesting piece about coming through the five stages of programming language grief, while wrestling with a .NET project written in Boo (a .NET language based on Python). That Scott should fall prey to the temptation to "doing things in the old way" (meaning he tried to port the project to C# because C# is, of course, the GOPL: God's Original Programming Language) is a touch surprising, because I tend to think more highly of Scott than that, but I have to admit having fallen into the same trap myself, so of course his sins are forgivable.
Amazing, isn't it, how we can forgive or excuse people's actions when we find ourselves doing the same thing?
Anyway, Scott's post highlights the importance of understanding the "Zen" of a particular programming language--its idioms, its approaches, and its strengths/weaknesses/quirks--when you move into it. For most of us, it's always easier to move into new territory with an experienced guide to show you the way. For Java developers, a guide--or, rather, a pair of them--have just made themselves available to you. Stu Halloway and Justin Gehtland (both ex-DevelopMentor instructors and, I'm privileged to say, friends of mine) have published "Rails for Java Programmers", a Java-centric guide to using Rails and Ruby, and a book I highly recommend, on the grounds that it helps "make Rails make sense" for developers used to the traditional Model/View/Controller approach in Java web apps. Weighing in at a pretty reasonable 300+ pages, it's probably one of the most gentle introductions to Rails that I've yet seen, and it's minus all the distractions of Why the Lucky Stiff's intro to Ruby.
Have a look--there's a sample chapter on InfoQ.