Data Nucleus Access Platform Note: This post is just my running notes and contains content consolidated from different sources while understanding datanucleus. DataNucleus (formerly known as Java Persistent Objects JPOX ) is an open source project (under the Apache 2 license) which provides a series of software products around data management in Java . DataNucleus Access Platform is a fully compliant implementation of the Java Data Objects (JDO) 1.0, 2.0, 2.1, 2.2, 3.0 specifications and the Java Persistence API 1.0, 2.0 specifications, providing transparent persistence of Java objects. It supports persistence to the widest range of datastores of any Java persistence software, supporting all of the main object-relational mapping (ORM) patterns, allows querying using either JDOQL , JPQL or SQL , and comes with its own byte-code enhancer. It allows persistence to relational datastores ( RDBMS ), object-based datastores ( db4o , NeoDatis ODB ), document-based storage( XML , Excel