This figure illustrates the relationship between EclipseLink components. Information stored in a database or in XML documents is transmitted to EclipseLink through a data source or JDBC.

EclipseLink includes the open source implementation of the Java Persistence API (JPA) specification, plus extensions beyond what is defined in JPA. EclipseLink also includes the Java API for XML Binding (JAXB) specification. These extensions include persistence unit properties, query hints, annotations, EclipseLink's XML metadata, and EclipseLink's custom API. which contains JPA, JAX/SDO, and DBWS.