Scala and Clojure both involve lots of new ways of thinking. This is why I like them. I suspect it is also a reason many hesitate to try or switch to them. People say you can use Scala as basically java with less boilerplate, but if you want to read other people's code, you need to understand a whole lot of new concepts. With Clojure there's no pretending you won't need to learn a bunch of new concepts. With Xtend however, the changes are limited enough that it can be a palatable first step for the hesitant.