Clojure is easier to learn then Java if your not allready set in Java ways and even if you are then you will have to learn a lot of the Clojure lessens in Java. Going more towards parallel und concurent systems immutebility has proven to be the better default and that what Java Books teach too. Once you get that in your head learning Clojure want look half as bad.
Not every Java team will just use Clojure or Scala but the trend in Industrie atm is to be open to all kinds of new stuff like FP, NoSQL, TDD, CI, XP ...
Its likely that Clojure will not get steam like Java or C but that alternativ Solution can be much better then sitting at your old tech-stack and that message will eventually even drop threw to mangers. Its a bottum up "revolution".
[2] !!!
In fact, your typical Blub programmer probably would lose long term productivity forcing himself to work in a lisp instead of a language well focused on his strengths. A Java or C-octothorpe sharply aimed at a coder only one or two standard deviations smarter than the average person will actually help him produce some kind of useful output.
But the community and popularity Clojure already has make it the most prominent lisp around for new projects and give it great long term prospects. This is the lisp that will be around in twenty years and probably the most popular lisp for most of that time.
[1] http://www.paulgraham.com/avg.html