Key features in Java EE 6

In this section, we will take a brief look over key features in Java EE 6.

In Java EE 6 some new features are added like Profiles. Some technologies is improved by adding annotations instead of XML in most of the technologies(Servlets 3.0, JPA 2.0). Some features are also removed completely, for example CMP of EJB because it is not widely used by the software developers.

The major changes in the Java EE 6 is given below :

Servlets 3.0

The major release in Java EE 6 is the new modified version of the Servlet technology. In the new version, you can declare servlet using annotation which makes the deployment descriptor optional.

Another step in making web tier simple is the Web Fragments .  For adding framework libraries such as Struts, Spring, JSF etc. you don't need to change the web.xml library. Servlets 3.0 have Web Fragments descriptor which  specify the details of each libraries which is used by the container.

Web Beans 1.0

The presentation layer(JSF, JSP, Servlet) and the persistence layer( JPA,EJB3.0, JCA, JTA) have getting bigger without much interaction. Presently no technology is present to integrate both tiers  web and persistence. The main reason for creating Web Beans is to short out this issue by defining beans which can communicate multiple tiers. The technologies in both the web tier is compatible with Web Beans.

JPA 2.0

The main features of the JPA 2.0 is given below :

• Modified object / relational mapping functionality.
  
  
• Java Persistence query language modifications
  
  
• API for criteria query
  
  
• Standardization of sets of "hints" for query configuration and for entity manager configuration
  
  
• Standardization of additional metadata to support DDL generation and "Java2DB" mapping
  
  
• Expanded pluggability contracts to support efficient passivation and replication of extended persistence contexts in Java EE environments
  
  
• Standardization of additional contracts for entity detachment and merge, and persistence context management
  
  
• Support for validation
  
  
•  Validation support.
  

JSF 2.0

JSF 2.0 have lot of new modifications. These changes are takes place by keeping in mind the comfort of development, fixes and new features, performance, Technology. To avoid faces-config.xml and web.xml lot of annotations are used in JSF 2.0 . Everything can be done through annotations how Servlets 3.0 has done.

In spite of that, JSF2.0 contains a lot of new promising features like expand the request processing lifecycle to be aware of Ajax, allow for bookmark JSF pages, provide a mechanism to easily access persistent store