Well, it's not all about the language. For me, and others, who are aware and have dwelved in advanced languages (such as Scala, Haskell, Lisp family), Java is often our choice for even hobby projects. It's not that we cannot see other languages's benefits. It's that in our opinion it's the best choice all things considered (how efficiently one can write readable/refactorable code being one of the most important things).

Kotlin seems to be one very good alternative in the future.