Java Persistence API (JPA) provides standard ORM technology to access a relational database. It replaces CMP entity bean provided in EJB.

JEUS supports all functions of the JPA specifications. JPA is defined as part of the JPA 2.1 specification in JSR 338, does not depend on an EJB container, and can be used by EJBs, web modules, and Java SE Standalone clients.

Moreover, JPA can be used by selecting a persistence provider implementation. JEUS provides the EclipseLink implementation classes of Eclipse Persistence Services Project by default.

Other implementations can also be selected for use. Refer to "3.1. Changing Persistence Provider" for more information.

When using JPA, you must consider both, the basic attributes of the APIs and the characteristics of the settings and providers, which are supported by the JPA specification. In particular, developing an application without considering an important attribute, such as caching, may not produce the desired result. Therefore, developers should develop an application with proper JPA configuration according to the environment. It is recommended to continue to refer to the EclipseLink JPA website, where such information will continue to be introduced using various patterns.

This document only covers the configurations for using the EclipseLink , the basic provider in JEUS. Refer to Reference Data to learn about JPA technology itself or programming methodology.