My theory is that the language's lack of complexity bothers 'high-end' Java devs at a subconscious level, so they think they have to invent it in order to seem relevant to the larger community. Another idea is they may believe elegance is a function of using powerful language constructs, rather than a function of minimalism.

I see the same problems in Ruby sometimes: metaprogramming used without a compelling need. Luckily it isn't as much of a PITA because nobody thinks its OK to program via XML files anymore.