DataNucleus Access Platform is a standards-compliant Java persistence product. It is fully compliant with the JDO1, JDO2, JDO2.1, and JPA1 Java standards. It also complies with the OGC Simple Feature Specification for persistence of geospatial Java types. It allows access to all popular RDBMSs available today, together with db4o, LDAP, Excel documents, and XML databases.
URL: DataNucleus - DataNucleus Access Platform