Understanding EclipseLink

EclipseLink is an open-source mapping and persistence framework for use in a Java environment, including Java Platform, Standard Edition (Java SE) and Java Platform, Enterprise Edition (Java EE). The EclipseLink project is under the stewardship of the Eclipse Foundation.

EclipseLink completely implements the following specifications, plus extensions to those specifications:

• Java Persistence API (JPA)

  JPA is the Java API for object/relational mapping (ORM), where Java objects are mapped to database artifacts, for the purpose of managing relational data in Java applications. JPA includes Java Persistence Query Language (JPQL), the Java Persistence Criteria API, and the Java API and XML schema for defining object/relational mapping metadata.

  The latest version of the specification is JSR 317: Java Persistence 2.0. See http://jcp.org/en/jsr/detail?id=317.

  Some of the EclipseLink extensions to standard JPA are:

  • Support for mapping to nonrelational (NoSQL) databases.

  • Features useful in Software as a Service (SaaS) environments, including tenant isolation, extensible entities, external metadata sources.

  • Java API for RESTful Web Services (JAX-RS, defined in JSR 311).

  • Many other additional annotations, annotation extensions, Java Persistence Query Language (JPQL) extensions, JPA query customizations extensions, and persistence property extensions.

• Java Architecture for XML Binding (JAXB)

  JAXB is the Java API for object/XML mapping (OXM), where an XML document is bound to Java objects, based on the XML document's XSD schema. JAXB provides methods for unmarshalling (reading) XML instance documents into Java content trees, and then marshalling (writing) Java content trees back into XML instance documents. JAXB also provides a way to generate XML schema from Java objects.

  The latest version of the specification is JSR 222: Java Architecture for XML Binding (JAXB) 2.0. See http://jcp.org/en/jsr/detail?id=222. J

  
  

  Note: The EclipseLink JAXB implementation is part of the EclipseLink MOXy component, which extends EclipseLink JAXB to support JavaScript Object Notation (JSON) documents. EclipseLink supports all object/XML options when reading and writing JSON. MOXy also includes support for the older native EclipseLink object/XML API).

  
  

In addition to the implementations of the standard specifications described above, EclipseLink includes the following:

• EclipseLink Database Web Services (DBWS)

  DBWS is a development tool and a runtime for providing Java EE-compliant, client-neutral access to relational database artifacts via a Web service. The development tool, DBWS Builder, is a command-line utility that generates the necessary deployment artifacts. (DBWS Builder is integrated into the Eclipse Dali Java Persistence toolset and into Oracle JDeveloper.) The runtime provider takes a service descriptor (along with related deployment artifacts) and realizes it as a JAX-WS 2.0 Web service. The runtime uses EclipseLink to bridge between the database and the XML SOAP Messages used by Web service clients.

• EclipseLink Enterprise Information Services (EIS)

  EIS is a facility for enabling the use of data stores through Java Connector Architecture (JCA) resource adapters. Using XML metadata, the interactions and their exchanged data are configured and mapped onto a domain model. The interactions data can be mapped from either the Common Client interface (CCI) or using XML schemas. This use is intended for non-relational data stores where no JDBC or SQL access is provided.

EclipseLink can be used with a wide range of Java Enterprise Edition (Java EE) and Java application architectures. Use EclipseLink to design, implement, deploy, and optimize an advanced, object-persistence and object-transformation layer that supports a variety of data sources and formats, including relational databases, nonrelational (NoSQL) databases, XML, JSON, and Web Services.

EclipseLink supports Java persistence in Java EE, Java SE and web containers including integration with various application servers including:

• Oracle WebLogic Server

• Oracle Glassfish Server

• JBoss Web Server

• IBM WebSphere application server

• SAP NetWeaver

• Oracle Containers for Java EE (OC4J)

• Various other web containers, such as Apache Tomcat, Eclipse Gemini, IBM WebSphere CE, and SpringSource Server

EclipseLink lets you quickly capture and define object-to-data source and object-to-data representation mappings in a flexible, efficient metadata format.

The runtime lets your application exploit this mapping metadata with a simple session facade that provides in-depth support for data access, queries, transactions (both with and without an external transaction controller), and caching.

For more information about EclipseLink, see "Key Features".