DataNucleus provides Java data persistence to a range of datastores using JDO/JPA/REST APIs. *** Note that code development is no longer on SourceForge (code on SourceForge is for versions up to 3.3.5 only) ***
Java persistence solution to bind Java objects to RDBMS tables.. you don't need to create XML files to describe relations between tables and objects. try it and feel the difference!
SPARQL to Object Oriented eNgine allows users to expose their traditional data sources (RDBMS, OODBMS, XML, LDAP, ecc) as RDF data, through a SPARQL endpoint.
Flexoodb stands for Flexible Object Oriented Database API. Using your choice of RDBMS, Flexoodb represents objects as XML, allows proprietary Serializable objects to be embedded within the XML representation and manipulation using extended classes.