Task overview: Store and retrieve persistent data with the JPA API
The Java Persistence API (JPA) for the application server defines the management of persistence and object and relational mapping within Java Enterprise Edition (Java EE) and Java Standard Edition (Java SE) environments.
JPA simplifies the persistence programming model. JPA functions within the Java EE specification for EJB 3.0 and later requirements, managing persistence and object and relational mapping. The JPA specification defines the object/relational mapping within its own guidelines instead of relying on vendor-specific mapping implementations. These features make applications that use JPA easier to implement and manage.
JPA combines features from previous persistence mechanisms such as JDBC APIs, Object Relational Mapping (ORM) frameworks, and Java Data Objects (JDO). Creating entities under JPA is as simple as Plain Old Java Objects (POJOs). JPA supports the features provided by JDBC without requiring the knowledge of the specific programming models defined by the various JDBC implementations. Like object-relational software and object databases, JPA supports the use of advanced object-oriented concepts such as inheritance. JPA avoids vendor lock-in because it does not rely on a strict specification like JDO and EJB 2.x entities.
The JPA implementation does not mandate that we migrate existing applications. Existing EJB 2.x Container Managed Persistence applications continue to work without changes. JPA might not be ideal for every application, however, for many applications it provides a better alternative to other persistence implementations.
JPA for WAS can be used on all platforms supported for the application server, including iSeries and z/OS . JPA for WAS supports all databases supported for the application server, including DB2 and Oracle. JPA for WAS (WSJPA) also functions with databases supported by the OpenJPA implementation of JPA.
Important: Databases supported by OpenJPA, but not supported by the WSJPA, have not been tested extensively by IBM, and might contain unknown compatibility issues.
For information about JPA specifications, see the related links. The information resides on both IBM and non-IBM Internet sites, whose sponsors control the technical accuracy of the information. Often, the information is not specific to this product but is useful all or in part for understanding the product. When possible, links are provided to technical papers and Redbooks that supplement the broad coverage of the release documentation with in-depth examinations of particular product areas.
Related:
Java Persistence API (JPA) architecture WSJPA for WAS Database generated version ID with WSJPA WAS persistence providers Associating persistence providers and data sources Troubleshoot JPA applications Use WSJPA access intent Logging applications with JPA Developing JPA 2.x applications for a Java EE environment Developing JPA 2.x applications for a Java SE environment Assembling a JPA application in a Java EE environment Assembling JPA applications for a Java SE environment Data source minimum required settings, by vendor JSR 317: Java Persistence 2.0 JSR 338: Java Persistence 2.1 Getting Started with the Feature Pack for OSGi Applications and JPA 2.0 Redbooks