DataNucleus (formerly known as Java Persistent Objects JPOX) is an open source project (under the Apache 2 license) which provides software products around data management in Java.

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, OpenDocument spreadsheets), web-based storage (JSON, Google Storage, Amazon Simple Storage Service), map-based datastores (HBase, Google's Bigtable, Apache Cassandra), graph-based datastores (Neo4j), document stores (MongoDB) as well as other types of datastores (e.g. LDAP).

Its plugins are OSGi-compliant so can be used equally in an OSGi environment.

DataNucleus Access Platform is also utilised by the persistence layer behind Google App Engine for Java,[7] and VMForce (cloud offering from Salesforce.com and VMWare).