If you post an advert for a Haskell developer you will get 20 applicants. All of those people will be the kind of developer who learns new programming languages to improve their own abilities and stretch themselves, because nobody yet learns Haskell just to get a job.
If you post an advert for a Java developer you will get 200 applicants. Most of them will be the kind of developer who learned Java because there are lots of Java jobs out there, and as long as they know enough to hold down a job then they see no reason to learn anything.
If you're a 100% Java coder, you'll always have a job, and there are legitimately interesting things that are happening in the Java world... but its pretty far from a majority in any sense. The problem with Java is that there are too many jobs that only need passable engineers. There are too many Java engineers who are plug-and-chug.
It's all about the hobbyist languages. That's where the magic happens. If you're a Java engineer, you should pick up Ruby on Rails at least -- it'll be a breath of fresh air.