[PommeDeTerre]

This isn't about my opinion or preferences. This is about looking at the reality of the situation.

Java (the language) is quite heavily used, but this is more a factor of it merely being around for years, and the huge amount of hype it received during its first decade of existence. However, it is now widely accepted that it is significantly deficient in many ways, which is part of the reason that people are seriously looking to alternatives.

Clojure may be a major player within the context of modern Lisp-like languages, but beyond that it's extremely obscure, and it is not widely used at all. At least part of this obscurity is due to its syntax and semantics. Time and time again we've seen this approach rejected by the software development community as a whole, regardless of whether we're talking about Lisp, Scheme, Common Lisp, and now Clojure. It's just not what people want.

So Scala ends up being the one with the fewest drawbacks, and the most positive aspects. It has a far more familiar syntax and semantics, it is seeing actual real-world use, and it does have features and functionality that attract people toward using it. From an objective viewpoint, it is the best of the given options.