J2EE Components

 J2EE specifies both the service API for building the application and the infrastructure for managing the applications. The J2EE platform is a distributed Application Server environment:

• A runtime infrastructure for managing and hosting applications. All runtime applications are located in this server.

• A set of java API to build applications. These Java API describe the programming model for J2EE applications.

J2EE Runtime Environment (JRE)

The J2EE specification does not specify how the J2EE runtime came into existence, instead J2EE specifies the role and interfaces for the application and the runtime on which application could be deployed. This characteristic allows the runtime to delineate most of the infrastructure services that any enterprise developers have attempted to build on their own. This shows that the J2EE Application developer could just focus on the application logic and related services, while leveraging the runtime for all infrastructure-related services.

J2EE API

In the Enterprise services, the distributed applications require access. These Enterprise services include transaction processing, managing, multithreading, database access etc. The J2EE architecture unifies access to such services in its enterprise service API. The application program in J2EE can access these API through the containers. A typical commercial J2EE platform consists of one or more containers and access to the enterprise API is specified by J2EE.

The Java 2 Platform, Standard Edition (J2SE) SDK is required to run the J2EE SDK and provides core APIs for writing J2EE components, core development tools, and the Java Virtual Machine (JVM). The J2EE SDK provides the following APIs to be used in J2EE applications.

1. Enterprise Java Beans (EJB) Technology

2. Java Servlet Technology

3. Java Server Pages (JSP) Technology

4. Java Server Faces (JSF)

5. Java Messaging Service (JMS)

6. Java Transaction API (JTA)

7. Java Mail API

8. Java Beans Activation Framework

9. Java API for XML

10. Java API for XML Based RPC (JAX-RPC)

11. SOAP with Attachments API for Java (SAAJ)

12. Java API for XML Registries (JAXR)

13. J2EE Connector API

14. JDBC

15. Java Naming and Directory Interface (JNDI)

16. Java Authentication and Authorization Service (JAAS)