Oracle has released Berkeley DB 4.7. This is a non-relational, key-value database. "Berkeley DB Java Edition (JE) provides an easy method for object storage, query, and retrieval. That's now been added to Berkeley DB's Java/JNI API. The Direct Persistence Layer (DPL) adds a built-in Plain Old Java Object (POJO)-based persistent object model, which provides support for complex object models."