Apache OpenJPA

OpenJPA is a free solution for persistence of Java objects in relational databases. OpenJPA implements the Java Persistence API 2.0 specification.

The main task of OpenJPA is the Object-relational mapping (OR mapping, short ORM). This enables ordinary objects with attributes and methods ( referred to in the Java section POJOs ) to be stored in a relational database, and to generate data sets of respective objects in turn. Relationships between objects are mapped to corresponding database relations.

History

The Java Data Objects ( JDO ) implementation Kodo was originally developed by Solar Metric 2001. Solar Metric was bought by BEA Systems 2005; Kodo was expanded by BEA to both the JDO specification, and the Java Persistence API (JSR 220) to support specification. 2006 BEA donated a large part of the Kodo source code of the Apache Software Foundation as OpenJPA.

BEA itself uses OpenJPA as the core persistence engine of BEA Weblogic application server. Furthermore OpenJPA is also in the IBM WebSphere and Apache Geronimo application server. May 2007, OpenJPA a top-level project of the Apache Software Foundation and has also passed regarding the implementation of Sun's Java Persistence API Technology Compatibility Kit.