The Enterprise JavaBeans (EJB) 3.0 specification includes an additional persistence specification called the Java Persistence API (JPA). It is an API for creating, removing and querying across lightweight Java objects and can be used both within a compliant EJB 3.0 Container and a standard Java SE 5 environment.

TopLink Essentials is the open-source community edition of Oracle's TopLink product. It provides the JPA functionality for the EJB 3.0 Reference Implementation.

JSR 220: Download the Specification