Java, as a language, is pretty easy to learn. If you already know the standard library from Scala/Clojure, even more so. That said, some parts of the ecosystem

Java, as a language, is pretty easy to learn. If you already know the standard library from Scala/Clojure, even more so. That said, some parts of the ecosystem that are built around (Enterprise) Java are real behemoths and the companies may actually be looking for experience with a particular framework/library than just generic Java experience.