Java Platform, Enterprise Edition

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Java Platform, Enterprise Edition or Java EE is Oracle's enterprise Java computing platform. The platform provides an API and runtime environment for developing and running enterprise software, including network and web services, and other large-scale, multi-tiered, scalable, reliable, and secure network applications. Java EE extends the Java Platform, Standard Edition (Java SE), providing an API for object-relational mapping, distributed and multi-tier architectures, and web services. The platform incorporates a design based largely on modular components running on an application server. Software for Java EE is primarily developed in the Java programming language. The platform emphasizes Convention over configuration and annotations for configuration. Optionally XML can be used to override annotations or to deviate from the platform defaults.

Version History

Main article: Java EE version history

The platform was known as Java 2 Platform, Enterprise Edition or J2EE until the name was changed to Java Platform, Enterprise Edition or Java EE in version 5. The current version is called Java EE 6.

• J2EE 1.2 (December 12, 1999)
• J2EE 1.3 (September 24, 2001)
• J2EE 1.4 (November 11, 2003)
• Java EE 5 (May 11, 2006)
• Java EE 6 (Dec 10, 2009)
• Java EE 7 (Not yet released, tentative release date April, 2013 )

Standards and specifications

Java EE is defined by its specification. As with other Java Community Process specifications, providers must meet certain conformance requirements in order to declare their products as Java EE compliant.

Java EE includes several API specifications, such as JDBC, RMI, e-mail, JMS, web services, XML, etc., and defines how to coordinate them. Java EE also features some specifications unique to Java EE for components. These include Enterprise JavaBeans, Connectors, servlets, JavaServer Pages and several web service technologies. This allows developers to create enterprise applications that are portable and scalable, and that integrate with legacy technologies. A Java EE application server can handle transactions, security, scalability, concurrency and management of the components that are deployed to it, in order to enable developers to concentrate more on the business logic of the components rather than on infrastructure and integration tasks.

General APIs

The Java EE APIs includes several technologies that extend the functionality of the base Java SE APIs.

• Java EE 6 Platform Packages
• Java EE 5 Platform Packages

javax.faces.*

This package defines the root of the JavaServer Faces (JSF) API. JSF is a technology for constructing user interfaces out of components.

javax.faces.component.*

This package defines the component part of the JavaServer Faces (JSF) API. Since JSF is primarily component oriented, this is one of the core packages. The package overview contains a UML diagram of the component hierarchy.

javax.servlet.*

The servlet specification defines a set of APIs to service mainly HTTP requests. It includes the JavaServer Pages specification.

javax.enterprise.inject.*

These packages define the injection annotations for the contexts and Dependency Injection (CDI) API's.

javax.enterprise.context.*

These packages define the context annotations and interfaces for the Contexts and Dependency Injection (CDI) API.

javax.ejb.*

The Enterprise JavaBean (EJB) specification defines a set of lightweight APIs that an object container (the EJB container) will support in order to provide transactions (using JTA), remote procedure calls (using RMI or RMI-IIOP), concurrency control, dependency injection and access control for business objects. This package contains the Enterprise JavaBeans classes and interfaces that define the contracts between the enterprise bean and its clients and between the enterprise bean and the ejb container.

javax.validation.*

This package contains the annotations and interfaces for the declarative validation support offered by the Bean Validation API. Bean Validation provides a unified way to provide constraints on beans (e.g. JPA model classes) that can be enforced cross-layer. In Java EE, JPA honors bean validation constraints in the persistence layer, while JSF does so in the view layer.

javax.persistence.*

This package contains the classes and interfaces that define the contracts between a persistence provider and the managed classes and the clients of the Java Persistence API (JPA).

javax.transaction.*

This package provides the Java Transaction API (JTA) that contains the interfaces to interact with the transaction support offered by Java EE. Even though this API abstracts from the really low-level details, it is itself also considered somewhat low-level and the average application developer in Java EE is assumed to be relying on transparent handling of transactions by the higher level EJB abstractions.

javax.jms.*

This package defines the Java Message Service (JMS) API. The JMS API provides a common way for Java programs to create, send, receive and read an enterprise messaging system's messages.

javax.resource.*

This package defines the Java EE Connector Architecture (JCA) API. Java EE Connector Architecture (JCA) is a Java-based technology solution for connecting application servers and enterprise information systems (EIS) as part of enterprise application integration (EAI) solutions. This is a low-level API aimed at vendors that the average application developer typically does not come in contact with.

Certified application servers

App Server	Java EE 6 certified - Full Official Oracle page for Java EE Compatibility.	Java EE 6 certified - Web	Java EE 5 certified	J2EE 1.4 certified	Licensing
GlassFish server Open Source Edition	Yes v3.x and upward	Yes v3.x Web Profile	Yes v2.1.x		Free software
Oracle GlassFish Server	Yes v3 based on the open source GlassFish application server		Yes Sun Java System Application Server v9.0	Yes Sun Java System Application Server v8.2	Proprietary software
Oracle WebLogic Server	Yes v12c		Yes v10.3.5.0	Yes v9	Proprietary software
JBoss Application Server	Yes v7.1	Yes v6.0 [1] and v7.0 [2]	Yes v5.1	Yes v4.x	Free software
JBoss Enterprise Application Platform	Yes v6.0		Yes v5
OW2 JOnAS	No v5.3 in development	Yes v5.3 rc1	Yes	Yes	Free software
IBM WebSphere Application Server	Yes v8		Yes v7	Yes	Proprietary software
IBM WebSphere Application Server Community Edition	Yes v3.0		Yes v2.1		Proprietary software
Apache Geronimo	Yes v3.0-beta-1 [3]		Yes v2.0	Yes v1.0	Free software
Fujitsu Interstage Application Server	Yes v1		Yes		Proprietary software
TmaxSoft JEUS	Yes v7		Yes v6	Yes v5	Proprietary software
Caucho Resin Server		Yes v4.0.		Yes	Proprietary software
Apache TomEE		Yes			Free software
SAP NetWeaver		Yes v2.x	Yes	Yes	Proprietary software
Oracle iPlanet Web Server				Yes Sun Java System Web Server	Proprietary software
Oracle Containers for Java EE			Yes		Proprietary software
NEC WebOTX			Yes		Proprietary software
Oracle Application Server 10g				Yes	Proprietary software
Pramati Server				Yes v5.0	Proprietary software
Trifork T4				Yes	Proprietary software
Sybase Enterprise Application Server				Yes	Proprietary software

Differences between implementations

Although by definition all Java EE implementations provide the same base level of technologies (namely, the Java EE spec and the associated APIs), they can differ considerably with respect to extra features (like connectors, clustering, fault tolerance, high availability, security, etc.), installed size, memory footprint, startup time, etc.

Code Sample

The code sample shown below demonstrates how various technologies in Java EE 6 are used together to build a web form for editing a user.

Example of UI page

In Java EE a (web) UI can be built using Servlet, JavaServer Pages (JSP), or JavaServer Faces (JSF) with Facelets. The example below uses JSF and Facelets. Not explicitly shown is that the input components use the Java EE Bean Validation API under the covers to validate constraints.

<html xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core">
 
    <f:metadata>
        <f:viewParam name="user_id" value="#{userEdit.user}" converter="#{userConvertor}" />
    </f:metadata>
 
    <h:body>
 
        <h:messages />
 
        <h:form>        
            <h:panelGrid columns="2">                                  
                <h:outputLabel for="firstName" value="First name" />
                <h:inputText id="firstName" value="#{userEdit.user.firstName}" label="First name" />
 
                <h:outputLabel for="lastName" value="Last name" />
                <h:inputText id="lastName" value="#{userEdit.user.lastName}" label="Last name"  />
 
                <h:commandButton action="#{userEdit.saveUser}" value="Save" />
            </h:panelGrid>
        </h:form>
 
    </h:body>
</html>

Example Backing Bean class

To assist the view, Java EE uses a concept called a "Backing Bean". The example below uses contexts and Dependency Injection (CDI) and Enterprise JavaBean (EJB).

@Named
@ViewScoped
public class UserEdit {
 
    private User user;
 
    @Inject
    private UserDAO userDAO;
 
    public String saveUser() {
        this.userDAO.save(this.user);        
        addFlashMessage("User " + this.user.getId() + " saved");
 
        return "users.xhtml?faces-redirect=true";
    }
 
    public void setUser(User user) {
        this.user = user;
    }
 
    public User getUser() {
        return this.user;
    }
}

Example DAO class

To implement business logic, Enterprise JavaBean (EJB) is the dedicated technology in Java EE. For the actual persistence, JDBC or Java Persistence API (JPA) can be used. The example below uses EJB and JPA. Not explicitly shown is that JTA is used under the covers by EJB to control transactional behavior.

@Stateless
public class UserDAO {
 
    @PersistenceContext
    private EntityManager entityManager;
 
    public void save(User user) {
        entityManager.persist(user);
    }
 
    public void update(User user) {
        entityManager.merge(user);
    }
 
    public List<User> getAll() {
        return entityManager.createNamedQuery("User.getAll", User.class)
                            .getResultList();
    }
 
}

Example Entity class

For defining entity/model classes Java EE provides the Java Persistence API (JPA), and for expressing constraints on those entities it provides the Bean Validation API. The example below uses both these technologies.

@Entity
public class User {
 
    @Id
    @GeneratedValue(strategy = IDENTITY)
    private Integer id;
 
    @Size(min = 2, message="First name too short")
    private String firstName;
 
    @Size(min = 2, message="Last name too short")
    private String lastName;
 
    public Integer getId() {
        return this.id;
    }
 
    public void setId(Integer id) {
        this.id = id;
    }
 
    public String getFirstName() {
        return this.firstName;
    }
 
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
 
    public String getLastName() {
        return this.lastName;
    }
 
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
 
}

See also

• Web container
• Deployment Descriptor
• Java BluePrints
• Sun Java System Portal Server
• Java EE version history
• Sun Community Source License
• Java Research License

External links

• Oracle Technology Network's Java EE
• Oracle's Java EE Compatibility page - Certified Java EE Compatible Implementations
• Core J2EE Patterns
• A short tutorial introducing beginning Java EE developers to the Java EE platform