There are plenty of reasons to learn a language - but Java in particular is a great learning tool. Whilst I don't enjoy developing in it (or its derivatives), I think that it's a great language to help people clearly understand control structure and polymorphism.

To this day, my experience continues to be that students who had a CS degree that included Java have significantly better fundamentals than those whose programme didn't. Whilst that's purely anecdotal, I'll definitely continue to skew this way until I see otherwise.