If you never looked into Spring Data, Tobias Trelle’s article could give you a brief overview:
Spring Data is a high level SpringSource project whose purpose is to unify and ease the access to different kinds of persistence stores, both relational database systems and NoSQL data stores.
The article is pretty clear why unification for the various relational and NoSQL databases won’t really work. The part left is ease of access, which in itself could still be an achievement. But without the unifying part I think Spring Data is just the Spring way of doing NoSQL for Spring users and not a general solution that non-Spring users would benefit of. I’m aware I’ve said this before.
Original title and link: Spring Data: One API to Rule Them All or Giving NoSQL to Spring Users ( ©myNoSQL)