WAS v8.5 > WebSphere applications > EJB applications > JPA architectureJPA for WAS
Java Persistence API (JPA) 2.0 for WebSphere Application Server is built on the Apache OpenJPA 2.x open source project.
Apache OpenJPA is a compliant implementation of the JPA specification. Using OpenJPA as a base implementation, WAS employs extensions to provide additional features and utilities for WAS customers. Because JPA for WAS is built from OpenJPA, all OpenJPA function, extensions, and configurations are unaffected by the WAS extensions. We do not need to make changes to OpenJPA applications to use these applications in WAS.
JPA for WAS provides more than compatibility with OpenJPA. JPA for WAS contains a set of tools for application development and deployment. Other features of JPA for WAS include support for DB2 Optim™ pureQuery Runtime, DB2 optimizations, JPA Access Intent, enhanced tracing capabilities, command scripts, and translated message files. The provider of JPA for WAS is com.ibm.websphere.persistence.PersistenceProviderImpl.
Apache OpenJPA supports the use of properties to configure the persistent environment. JPA for WAS properties can be specified with either the openjpa or wsjpa prefix. We can mix the openjpa and wsjpa prefixes as you wish for a common set of properties. Exceptions to the rule are wsjpa specific configuration properties, which use the wsjpa prefix. When a JPA for WAS-specific property is used with the openjpa prefix, a warning message is logged indicating the offending property is treated as a wsjpa property. The reverse does not hold true for the openjpa prefix. In that case, the offending property is ignored.
Related
Configure the JPA default persistence provider
Related information:
Apache OpenJPA User Guide: Configuration properties