Java JEE 6
Java EE, JEE or Java Platform, Enterprise Edition is a java standard-plattform for developing Enterprise applications. These are multitier applications for frontend
(web applications), middle(security and transactions application) and backend (communication with persistence like database or legacy system).
JEE 6 provides as well naming service (JNDI), injection (CDI), resource management, persistence API JAP.
With Java EE 6 the developing of application is now easy. So it takes the way convention over configuration. It means it preferes the use of annotation
in java code over configuration in xml files.
Therfore in JEE 6 the configuration files are in most cases optional. The most information in config-files are now directly provided in java code through annotetions.
Annotaions make easy to convert a POJO (Pain Old Java Object) e. g. with @Stateless, @Stateful or @Singelton to a Enterprise Bean. A Enterprise Bean can be Stateless Bean, Stateful Bean or Singelton Bean or Message Driven Bean
It also makes with @WebServlet a POJO to a Servlet or with @WebService to a web service or @Path to a Restful Webservice.
There are over 30 components in Java EE 6. Some of these components are relevant and some other are eihther replaced or no longer used. We will discuss the following components:
1. Servlet 3.0
2. JSP
3. Java Server Faces JSF 2.0 and EL
4. Java API for XML Web Service JAX-WS
5. Java Architicture for XML Binding
6. Java API for Restful Web Service JAX-RS
7. Bean Validation
8. Context and Dependency Injection CDI
9. Interceptor
10. Enterprise Java Bean EJB 3.1
11. Managed Bean
12. Java Persistence API JPA 2.0
13. Java Transaction API JTA
14. Java Message Server JMS
15. JNDI
16. Java Mail
The components are no longer used will in be removed in any steps from the JEE platform. It makes JEE platform lightweight and simple to use and maintain.
Java EE 6 provied also possibility of extension. So the third party framework can be put and used. From the view of my point it would be the best, if possible, to avoid the use of third party package and stay on standard.
If there is no way or because many applications based on third party package already implementetd. then it would be prefered to use the third party packages or framewroks.
There are some new feutures added in Java JEE to improve the functionality and richness the JEE plattform.
E.g. a method of session bean can be marked as asynchronous. Or a bean method can be annotated as @Schedule to be excuted time-based.
EJB API and Client API are allowed to run within the same JVM and the classloader.
Frameworks can be integrated in a way using web-fragment.xml.