Java Platform, Enterprise Edition

Java Platform, Enterprise Edition or Java EE is a widely used enterprise computing platform developed under the Java Community Process. 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),[1] 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[2] and annotations for configuration. Optionally XML can be used to override annotations or to deviate from the platform defaults.

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 7.

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 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 it is deploying, 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.

javax.servlet.*

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

javax.websocket.*

The Java API for WebSocket specification defines a set of APIs to service WebSocket connections.

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 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.el.*

This package defines the classes and interfaces for Java EE's Expression Language. The Expression Language (EL) is a simple language originally designed to satisfy the specific needs of web application developers. It is used specifically in JSF to bind components to (backing) beans and in CDI to name beans, but can be used throughout the entire platform.

javax.enterprise.inject.*

These packages define the injection annotations for the Contexts and Dependency Injection (CDI) APIs.

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 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 and annotations to interact with the transaction support offered by Java EE. Even though this API abstracts from the really low-level details, the interfaces are also considered somewhat low-level and the average application developer in Java EE is either assumed to be relying on transparent handling of transactions by the higher level EJB abstractions, or using the annotations provided by this API in combination with CDI managed beans.

javax.security.auth.message.*

This package provides the core of the Java Authentication SPI (JASPIC) that contains the interfaces and classes to build authentication modules for secure Java EE applications. Authentication modules are responsible for the interaction dialog with a user (e.g. redirecting to a Form or to an OpenID provider), verifying the user's input (e.g. by doing an LDAP lookup, database query or contacting the OpenID provider with a token) and retrieving a set of groups/roles that the authenticated user is in or has (e.g. by again doing an LDAP lookup or database query).

javax.enterprise.concurrent.*

This package provides the interfaces for interacting directly with Java EE's platform default managed thread pool. A higher-level executor service working on this same thread pool can be used optionally. The same interfaces can be used for user-defined managed thread pools, but this relies on vendor specific configuration and is not covered by the Java EE specification.

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.batch.api.*

This package defines the entry AP for Java EE Batch Applications. The Batch Applications API provides the means to run long running background tasks that possibly involve a large volume of data and which may need to be periodically executed.

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.

Web profile

In an attempt to limit the footprint of web containers, both in physical and in conceptual terms, the web profile was created, a subset of the Java EE specifications. The Java EE web profile comprises the following:

Specification Java EE 6[6] Java EE 7[3]
Servlet 3.0 3.1
JavaServer Pages (JSP) 2.2 2.3
Unified Expression Language (EL) 2.2 3.0
Debugging Support for Other Languages (JSR-45) 1.0 1.0
JavaServer Pages Standard Tag Library (JSTL) 1.2 1.2
JavaServer Faces (JSF) 2.0 2.2
Java API for RESTful Web Services (JAX-RS) 1.1 2.0
Java API for WebSocket (WebSocket) n/a 1.0
Java API for JSON Processing (JSON-P) n/a 1.0
Common Annotations for the Java Platform (JSR-250) 1.1 1.2
Enterprise JavaBeans (EJB) 3.1 Lite 3.2 Lite
Java Transaction API (JTA) 1.1 1.2
Java Persistence API (JPA) 2.0 2.1
Bean Validation 1.0 1.1
Managed Beans 1.0 1.0
Interceptors 1.1 1.2
Contexts and Dependency Injection for the Java EE Platform 1.0 1.1
Dependency Injection for Java 1.0 1.0

Certified application servers

App Server Java EE 7 certified - Full Java EE 7 certified - Web 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 v4.0[7] Yes v4.0[7] Yes v3.x and upward[8] Yes v3.x Web Profile Yes v2.1.x[8] Free software
Oracle GlassFish Server Yes v3[9] 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 v12.2.1 [10][11][12] Yes v12c[13] Yes v10.3.5.0 Yes v9 Proprietary software
WildFly Yes v8.0.0.Final[14][15][16] Yes v8.0.0.Final Yes v7.1[17] Yes v6.0[18] and v7.0[19] Yes v5.1[20][21] Yes v4.x Free software
JBoss Enterprise Application Platform Yes v6.0[22] Yes v5 Source is Free software
IBM WebSphere Application Server Yes v8[23] Yes v7 Yes Proprietary software
IBM WebSphere Application Server Liberty Yes v8.5.5.6 [24][25] Yes v8.5.5[26] Proprietary software
IBM WebSphere Application Server Community Edition Yes v3.0 Yes v2.1 Proprietary software
Apache Geronimo Yes v3.0-beta-1 [27] Yes v2.0 Yes v1.0 Free software
TmaxSoft JEUS Yes v8[28][29][30] Yes v7[31][32] Yes v6 Yes v5 Proprietary software
Hitachi Application Server Yes v10[33][34] Yes v9[35] Proprietary software
Fujitsu Interstage Application Server[36] Yes v1 Azure/v10.1[37][38] Yes Proprietary software
NEC WebOTX Yes[39] Yes Proprietary software
Caucho Resin Server Yes v4.0.[40] Yes Proprietary software
Apache TomEE[41][42] Yes Free software
OW2 Siwpas Yes v6.0[43] Free software
OW2 JOnAS Yes v5.3 rc1[44] Yes Yes Free software
SAP NetWeaver Yes v2.x[45] Yes Yes Proprietary software
Oracle Containers for Java EE Yes Proprietary software
Oracle iPlanet Web Server Yes Sun Java System Web Server 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[46] 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 7 are used together to build a web form for editing a user.

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://xmlns.jcp.org/jsf/html" xmlns:f="http://xmlns.jcp.org/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() {
        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 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 id;
    }
        
    public void setId(Integer id) {
        this.id = id;
    }
  
    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
        
    public String getLastName() {
        return lastName;
    }
 
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

}

See also

References

  1. ↑ "Differences between Java EE and Java SE - Your First Cup: An Introduction to the Java EE Platform". Docs.oracle.com. 2012-04-01. Retrieved 2012-07-18.
  2. ↑ http://jdevelopment.nl/minimal-3tier-java-ee-app-xml-config
  3. 1 2 http://jcp.org/en/jsr/detail?id=342
  4. ↑ https://blogs.oracle.com/java/entry/introducing_java_ee_7
  5. ↑ https://blogs.oracle.com/theaquarium/entry/java_ee_8_roadmap_update
  6. ↑ http://jcp.org/en/jsr/detail?id=316
  7. 1 2 http://www.oracle.com/technetwork/java/javaee/overview/compatibility-jsp-136984.html
  8. 1 2 https://glassfish.dev.java.net/public/comparing_v2_and_v3.html
  9. ↑ "Java EE Compatibility". Java.sun.com. 2010-09-07. Retrieved 2012-07-18.
  10. ↑ http://docs.oracle.com/middleware/1221/wls/NOTES/whatsnew.htm#NOTES379
  11. ↑ https://blogs.oracle.com/theaquarium/entry/weblogic_now_java_ee_7
  12. ↑ http://www.oracle.com/technetwork/java/javaee/overview/oracleweblogic1211-2769862.html
  13. ↑ http://wcc.on24.com/event/37/57/27/rt/1/documents/player_docanchr_3/weblogic12c_launch_tech_webinar_v8.pdf
  14. ↑ wildfly.org/about/#compliant
  15. ↑ https://issues.jboss.org/browse/WFLY-469
  16. ↑ http://lists.jboss.org/pipermail/wildfly-dev/2013-May/000062.html
  17. ↑ "JBoss AS 7.1.0.Final "Thunder" released - Java EE 6 Full Profile certified! | My Wiki | Planet JBoss Community". Planet.jboss.org. 2012-02-17. Retrieved 2012-07-18.
  18. ↑
  19. ↑
  20. ↑ Java EE Compatibility
  21. ↑ JBoss AS is now EE5 certified
  22. ↑ Business Wire (2012-06-20). "Red Hat Launches JBoss Enterprise Application Platform 6 to Help Enterprises Move Application Development and Deployment to the Cloud". Business Wire. Retrieved 2012-07-18.
  23. ↑ "What's new in WebSphere Application Server V8". Ibm.com. Retrieved 2012-07-18.
  24. ↑ oracle.com/technetwork/java/javaee/overview/waslibertyprofile8556-2587134.html
  25. ↑ https://developer.ibm.com/wasdev/blog/2015/06/25/java-ee-7-has-landed-in-was-liberty
  26. ↑ http://www.oracle.com/technetwork/java/javaee/community/ibm-javaee6-web-tested-configs-1961333.html
  27. ↑ "Apache Geronimo fully certified for Java EE 6 - The H Open: News and Features". H-online.com. 2011-11-14. Archived from the original on 20 April 2012. Retrieved 2012-07-18.
  28. ↑ http://www.oracle.com/technetwork/java/javaee/community/tmax-jeus-8-tested-configuration-1995477.html
  29. ↑ http://tmaxsoft.com/product/jeus/certification
  30. ↑ https://blogs.oracle.com/theaquarium/entry/tmaxsoft_jeus_8_now_java
  31. ↑ "Tested Configurations, Java EE 6 - TMAX JEUS 7". Oracle.com. 2010-09-07. Retrieved 2012-07-18.
  32. ↑ "Java EE6 Web Application Server, WAS Software". Us.tmaxsoft.com. Retrieved 2012-07-18.
  33. ↑ http://oracle.com/technetwork/java/javaee/overview/hitachi-91-tested-configurations-2393447.html
  34. ↑ https://blogs.oracle.com/theaquarium/entry/hitachi_cosminexus_now_java_ee
  35. ↑ "Java EE 6 - Tested Configurations, Java EE 6 - Hitachi uCosminexus Application Server v9.0". Oracle.com.
  36. ↑ Fujitsu Interstage Application Server powered by Windows Azure
  37. ↑ "Tested Configurations, Java EE6 - Fujitsu Interstage". Oracle.com. 2010-09-07. Retrieved 2012-07-18.
  38. ↑ "Fujitsu Releases Interstage Application Server V10.1". Fujitsu.
  39. ↑ http://www.oracle.com/technetwork/java/javaee/community/nec-webotx-v9x-certification-2002719.html
  40. ↑ http://www.caucho.com/articles/Caucho_Web%20Profile%20JavaEE6_whitepaper_byRR.pdf
  41. ↑ "Apache TomEE". Openejb.apache.org. Retrieved 2012-07-18.
  42. ↑ "MarketWatch.com". MarketWatch.com. Retrieved 2012-07-18.
  43. ↑ "Please Welcome Siwpas as Java EE Certified Option!". Oracle.com. Retrieved 2015-12-07.
  44. ↑ http://jonas.ow2.org/xwiki/bin/view/Blog/JOnAS+530+RC1+released
  45. ↑ https://blogs.oracle.com/theaquarium/entry/sap_netweaver_cloud_java_ee
  46. ↑ EAServer

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