JPOX provides transparent persistence of Java objects. It fully complies with the JDO1.0/JDO2.0/JDO2.1/JPA1 specifications. It supports persistence to all of the major RDBMSs on the market today, as well as DB4O. It allows querying using JDOQL, SQL, or JPQL. It comes with its own byte-code enhancer. Its 1.1 release is Sun's "Reference Implementation" (RI) for JDO2.0, and its 1.2 release is the RI for JDO2.1. It is highly extensible, using OSGi technology and providing a wide range of value-adding plugins. License: The Apache License 2.0 Changes:
Two memory leaks were fixed. A bug was fixed in the generation of values. A significant performance improvement was made in the attachment of large object graphs where an object reference is present in more than one place. Support for DB4O Native queries was added. A bugfix was made to DB4O support for application identity.

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