Java Enterprise Edition 5
Byadmin on Mar 22, 2008 | In Java Enterprise Edition (JEE)
The Java Enterprise Edition 5 reduces the cost and complexity of developing multitier, enterprise services. Java EE applications can be rapidly deployed and easily enhanced as the enterprise responds to competitive pressures. Java Enterprise Edition is very powerful and has become the industry standard for building robust enterprise applications.
The specification for JEE is JSR 244 and is managed by the Java Community Process.
Ease of Development
The whole drive behind JEE5 is “Ease of Development”. This drive removes the complex coding previously needed in J2EE 1.4.
In JEE 5 the XML deployment descriptors are optional. The use of annotations in JEE5 enables the framework to make EJB’s and web service of POJO classes. The deployment or configuration information can be added to the source code as an annotation. The makes the development a lot easier and faster as the deployment or configuration information is now packaged with the actual source file it effects. The JEE 5 container will configure the component during the deployment and runtime of the application.
Dependancy Injection is another way that JEE 5 has increased the efficiency of the development of enterprise applications easier and faster. Dependancy Injection is used to lookup resources like EJB's or Datasources by effectively hiding the creation and lookup of these resources from the application. These resources are injected into the application code by making use of annotations, which informs the container to inject a reference to the appropriate resource.
The Java Persistence API is used to mapp a Relational database to the POJO classes in Java. Through annotations, these POJO classes are mapped to specific tables and fields within the relational database. The normal CRUD operations could then be performed on these POJO objects.
Annotations is one of the new features within the JEE 5 specification that hase made the drive for "Ease of Development" real.
Major Features of JEE5
- Simplified Web Services development.
- Simplified EJB development.
- Simplified Web development through JSF.
- Simplified Persistence Layer through JPA specification.
- Reduced use of XML Deployment and Configuration descriptors.
- Ease of development through use of Annotations.
- Ease of development through Dependency Injection.
Java EE Architecture
The following image shows the different JEE elements that the different containers provide as services. The Containers, denoted by the separate rectangles, are Java EE runtime environments that provide required services to the application components represented in the upper half of the rectangle. The services provided are denoted by the boxes in the lower half of the rectangle. The EJB container makes use of the JMS API for messaging that supports reliable point-to-point messaging as well as the publish-subscribe model.
Architectural Elements of Java EE 5
JEE Elements Version Java Specification Request Common Annotations 1.0 JSR 250 Java EE Deployment 1.1 JSR 088 Java EE Management 1.1 JSR 077 Java Metadata Specification JSR 175 Servlets 2.5 JSR 154 Web Services 1.2 JSR 109 Web Services Metadata 2.0 JSR 181 EJB 3.0 JSR 220 JAAS 1.0 JACC 1.1 JAF 1.1 JavaMail 1.4 JAXB 2.0 JSR 222 JAXP 1.3 JAXR 1.0 JAX-RPC 1.1 JAX-WS 2.0 JSR 224 JCA 1.5 JDBC 3.0 JMS 1.1 JNDI 1.2 JPA 1.0 JSR 220 JSE 5.0 JSF 1.2 JSR 252 JSP 2.1 JSR 245 JSTL 1.2 JSR 052 JTA 1.1 JTS 1.0 SAAJ 1.3 STAX 1.0 JSR 173
Each of these JEE elements will be discussed in seperate sections through out this website.
External Information
| « Distributed Multitiered Architecture | GlassFish – An Introduction » |
