I'd like to find simple storage engines or low-level databases, embeddable in Java. I.e. libraries.
They only have to be able to store bytes, really. Keys could be simply integers.
No querying required. I am investigating the idea of dealing with persistence or even implementing databases on top of such a simple foundation.
Of course, fast, lean, simple are good qualities.
(Wasn't able to use (create) additional tags: low-level, storage)