What is the Java 2 Platform, Enterprise Edition (J2EE)?
What are the main benefits of the J2EE platform?
Can the J2EE platform interoperate with other WS-I implementations?
What technologies are included in the J2EE platform?
What's new in the J2EE 1.4 platform?
What is the J2EE 1.4 SDK?
Which version of the platform should I use now -- 1.4 or 1.3?
Can applications written for the J2EE platform v1.3 run in a J2EE platform v1.4 implementation?
How is the J2EE architecture and the Sun Java Enterprise System related?
Can I get the source for the Sun Java System Application Server?
How can I learn about the J2EE platform?
What tools can I use to build J2EE applications?
Who needs the J2EE platform?
What do you mean by "Free"?
Is support "Free"?
Are there compatibility tests for the J2EE platform?
What is the difference between being a J2EE licensee and being J2EE compatible?
What is the relationship of the Apache Tomcat open-source application server to the J2EE SDK?
Q: What is the Java 2 Platform, Enterprise Edition (J2EE)?

The Java 2 Platform, Enterprise Edition (J2EE) is a set of coordinated specifications and practices that together enable solutions for developing, deploying, and managing multi-tier server-centric applications. Building on the Java 2 Platform, Standard Edition (J2SE), the J2EE platform adds the capabilities necessary to provide a complete, stable, secure, and fast Java platform to the enterprise level. It provides value by significantly reducing the cost and complexity of developing and deploying multi-tier solutions, resulting in services that can be rapidly deployed and easily enhanced.

Q: What are the main benefits of the J2EE platform?

The J2EE platform provides the following:

Complete Web services support. The J2EE platform provides a framework for developing and deploying web services on the Java platform. The Java API for XML-based RPC (JAX-RPC) enables Java technology developers to develop SOAP based interoperable and portable web services. Developers use the standard JAX-RPC programming model to develop SOAP based web service clients and endpoints. A web service endpoint is described using a Web Services Description Language (WSDL) document. JAX-RPC enables JAX-RPC clients to invoke web services developed across heterogeneous platforms. In a similar manner, JAX-RPC web service endpoints can be invoked by heterogeneous clients. For more info, see http://java.sun.com/webservices/.


Faster solutions delivery time to market. The J2EE platform uses "containers" to simplify development. J2EE containers provide for the separation of business logic from resource and lifecycle management, which means that developers can focus on writing business logic -- their value add -- rather than writing enterprise infrastructure. For example, the Enterprise JavaBeans (EJB) container (implemented by J2EE technology vendors) handles distributed communication, threading, scaling, transaction management, etc. Similarly, Java Servlets simplify web development by providing infrastructure for component, communication, and session management in a web container that is integrated with a web server.

Freedom of choice. J2EE technology is a set of standards that many vendors can implement. The vendors are free to compete on implementations but not on standards or APIs. Sun supplies a comprehensive J2EE Compatibility Test Suite (CTS) to J2EE licensees. The J2EE CTS helps ensure compatibility among the application vendors which helps ensure portability for the applications and components written for the J2EE platform. The J2EE platform brings Write Once, Run Anywhere (WORA) to the server.

Simplified connectivity. J2EE technology makes it easier to connect the applications and systems you already have and bring those capabilities to the web, to cell phones, and to devices. J2EE offers Java Message Service for integrating diverse applications in a loosely coupled, asynchronous way. The J2EE platform also offers CORBA support for tightly linking systems through remote method calls. In addition, the J2EE platform has J2EE Connectors for linking to enterprise information systems such as ERP systems, packaged financial applications, and CRM applications.

By offering one platform with faster solution delivery time to market, freedom of choice, and simplified connectivity, the J2EE platform helps IT by reducing TCO and simultaneously avoiding single-source for their enterprise software needs.
Q: Can the J2EE platform interoperate with other WS-I implementations?

Yes, if the other implementations are WS-I compliant.

Q: What technologies are included in the J2EE platform?

The primary technologies in the J2EE platform are: Java API for XML-Based RPC (JAX-RPC), JavaServer Pages, Java Servlets, Enterprise JavaBeans components, J2EE Connector Architecture, J2EE Management Model, J2EE Deployment API, Java Management Extensions (JMX), J2EE Authorization Contract for Containers, Java API for XML Registries (JAXR), Java Message Service (JMS), Java Naming and Directory Interface (JNDI), Java Transaction API (JTA), CORBA, and JDBC data access API.

Q: What's new in the J2EE 1.4 platform?

The Java 2 Platform, Enterprise Edition version 1.4 features complete Web services support through the new JAX-RPC 1.1 API, which supports service endpoints based on servlets and enterprise beans. JAX-RPC 1.1 provides interoperability with Web services based on the WSDL and SOAP protocols. The J2EE 1.4 platform also supports the Web Services for J2EE specification (JSR 921), which defines deployment requirements for Web services and utilizes the JAX-RPC programming model. In addition to numerous Web services APIs, J2EE 1.4 platform also features support for the WS-I Basic Profile 1.0. This means that in addition to platform independence and complete Web services support, J2EE 1.4 offers platform Web services interoperability.

The J2EE 1.4 platform also introduces the J2EE Management 1.0 API, which defines the information model for J2EE management, including the standard Management EJB (MEJB). The J2EE Management 1.0 API uses the Java Management Extensions API (JMX). The J2EE 1.4 platform also introduces the J2EE Deployment 1.1 API, which provides a standard API for deployment of J2EE applications.

The J2EE platform now makes it easier to develop web front ends with enhancements to Java Servlet and JavaServer Pages (JSP) technologies. Servlets now support request listeners and enhanced filters. JSP technology has simplified the page and extension development models with the introduction of a simple expression language, tag files, and a simpler tag extension API, among other features. This makes it easier than ever for developers to build JSP-enabled pages, especially those who are familiar with scripting languages.

Other enhancements to the J2EE platform include the J2EE Connector Architecture, which provides incoming resource adapter and Java Message Service (JMS) pluggability. New features in Enterprise JavaBeans (EJB) technology include Web service endpoints, a timer service, and enhancements to EJB QL and message-driven beans. The J2EE 1.4 platform also includes enhancements to deployment descriptors. They are now defined using XML Schema which can also be used by developers to validate their XML structures.

Q: What is the J2EE 1.4 SDK?

The Java 2 SDK, Enterprise Edition 1.4 (J2EE 1.4 SDK) is a complete package for developing and deploying J2EE 1.4 applications. The J2EE 1.4 SDK contains the Sun Java System Application Server Platform Edition 8, the J2SE 1.4.2 SDK, J2EE 1.4 platform API documentation, and a slew of samples to help developers learn about the J2EE platform and technologies and prototype J2EE applications. The J2EE 1.4 SDK is for both development and deployment.

Q: Which version of the platform should I use now -- 1.4 or 1.3?

The J2EE 1.4 specification is final and you can use the J2EE 1.4 SDK to deploy applications today. However, for improved reliability,scability, and performance, it is recommended that you deploy your applications on J2EE 1.4 commercial implementations that will be available early in 2004. If you want to deploy your application before 2004, and reliability,scability, and performance are critical, you should consider using a high performance application server that supports J2EE v1.3 such as the Sun Java System Application Server 7. Many application server vendors are expected to release J2EE platform v1.4 versions of their product before the spring.

Q: Can applications written for the J2EE platform v1.3 run in a J2EE platform v1.4 implementation?

J2EE applications that are written to the J2EE 1.3 specification will run in a J2EE 1.4 implementation. Backwards compatibility is a requirement of the specification.

Q: How is the J2EE architecture and the Sun Java Enterprise System related?

The J2EE architecture is the foundation of the Sun Java System Application Server, a component of the Sun Java Enterprise System. The Sun Java System Application Server in the current Sun Java Enterprise System is based on the J2EE platform v1.3, with additional support for Web services. Developers familiar with J2EE technology can easily apply their skills to building applications, including Web services applications, using the Sun Java Enterprise System. For more information, see the Sun Java Enterprise System Web site.

Q: Can I get the source for the Sun Java System Application Server?

You can get the source for the J2EE 1.4.1 Reference Implementation from the Sun Community Source Licensing site. The J2EE 1.4.1 Reference Implementation is the Sun Java System Application Server Platform Edition 8 minus the following components:

The installer
The Web-based administration GUI
JavaServer Faces 1.0 and JSTL 1.1
Solaris specific enhancements for security and logging
Higher performance message queue implementation

Q: How can I learn about the J2EE platform?

For more information about the J2EE platform and how to get the specification, see http://java.sun.com/j2ee/.

The most effective way to learn about the J2EE platform and what's new in the J2EE 1.4 platform is to get hands on experience with the APIs by using the J2EE 1.4 SDK. The J2EE 1.4 SDK provides a J2EE 1.4 compatible application server as the foundation to develop and deploy Web services enabled, multi-tier enterprise applications. You can download the J2EE 1.4 SDK from http://java.sun.com/j2ee/1.4/download.html

For beginners, the J2EE documentation page provides links to a wide variety of self-paced learning materials, such as tutorials and FAQs.

Developers looking for more advanced material should consult the Java BluePrints for the enterprise. The Java BluePrints for the enterprise are the best practices philosophy for the design and building of J2EE-based applications. The design guidelines document provides two things. First, it provides the philosophy of building n-tier applications on the Java 2 platform. Second, it provides a set of design patterns for designing these applications, as well as a set of examples or recipes on how to build the applications.

Sun educational services also provides many training courses, which can lead to can lead to one of three certifications: Sun Certified Web Component Developer, Sun Certified Business Component Developer, or Sun Certified Enterprise Architect.

What tools can I use to build J2EE applications?

There are numerous choices of tools available for developing Java and J2EE applications. You can download the Open Source NetBeans IDE for free at http://netbeans.org. Many of the J2EE compatible vendors offer tools that support any J2EE compatible application server.

Q: Who needs the J2EE platform?

ISVs need the J2EE platform because it gives them a blueprint for providing a complete enterprise computing solution on the Java platform. Enterprise developers need J2EE because writing distributed business applications is hard, and they need a high-productivity solution that allows them to focus only on writing their business logic and having a full range of enterprise-class services to rely on, like transactional distributed objects, message oriented middleware, and naming and directory services.

Q: What do you mean by "Free"?


When we say "Free" we mean that you don't pay Sun to develop or deploy the J2EE 1.4 SDK or the Sun Java System Application Server Platform Edition 8. Free means that you don't pay Sun for supplementary materials including documentation, tutorials and/or J2EE Blueprints. You are also free to bundle and distribute (OEM) Sun Java System Application Server Platform Edition 8 with your software distribution. When we say "Free", we mean "Free for All".

Here are some examples of how you can use Sun Java System Application Server Platform Edition 8 for free.

If you are a developer you can build an application with the J2EE 1.4 SDK and then deploy it on the Sun Java System Application Server Platform Edition 8 (included with the J2EE 1.4 SDK or available separately). No matter how many developers are on your team, all of them can use the J2EE 1.4 SDK at no charge. Once your application is ready for production, you can deploy including the Sun Java System Application Server Platform 8 Edition in production on as many servers or CPUs as you want.

If you are an ISV, you don't have to pay to include Sun Java System Application Server Platform Edition 8 with your product, no matter how many copies of your software that you distribute. Bundling Sun Java System Application Server Platform Edition 8 makes good business sense because it ensures that you are distributing a J2EE 1.4 platform compatible server that doesn't lock you or your customers into a proprietary product. ISV's that wish to bundle Sun Java System Application Server Platform Edition 8 (for free of course) should contact Sun OEM sales.

If you are a System Administrator or IT manager, you can install Sun Java System Application Server Platform Edition 8 on as many servers and CPUs as you wish. Using Sun Java System Application Server Platform Edition 8 also gives reduced cost and complexity by saving money on licensing fees and the assurance of a J2EE 1.4 platform compatible application server that can be used with other J2EE 1.4 platform compatible application servers.

Q: Is support "Free"?

There are resources that are available for free on our site that may help you resolve your issues without requiring technical support. For example you can ask questions on our forums, search for known issues on the bug data base, review the documentation, or take a look at code samples and applications to help you at no cost.

Production support is also available for a fee through Sun Service. For more information about Developer Technical Service and Sun Service, please visit http://wwws.sun.com/software/products/appsrvr/support.html.

Q: Are there compatibility tests for the J2EE platform?

Yes. The J2EE Compatibility Test Suite (CTS) is available for the J2EE platform. The J2EE CTS contains over 5,000 tests for J2EE 1.4 and will contain more for later versions. This test suite tests compatibility by performing specific application functions and checking results. For example, to test the JDBC call to insert a row in a database, an EJB component makes a call to insert a row and then a call is made to check that the row was inserted.

Q: What is the difference between being a J2EE licensee and being J2EE compatible?

A J2EE licensee has signed a commercial distribution license for J2EE. That means the licensee has the compatibility tests and has made a commitment to compatibility. It does not mean the licensees products are necessarily compatible yet. Look for the J2EE brand which signifies that the specific branded product has passed the Compatibility Test Suite (CTS) and is compatible.

Q: What is the relationship of the Apache Tomcat open-source application server to the J2EE SDK?

Tomcat is based on the original implementation of the JavaServer Pages (JSP) and Java Servlet specifications, which was donated by Sun to the Apache Software Foundation in 1999. Sun continues to participate in development of Tomcat at Apache, focusing on keeping Tomcat current with new versions of the specifications coming out of the Java Community Source ProcessSM. Sun adapts and integrates the then-current Tomcat source code into new releases of the J2EE SDK. However, since Tomcat evolves rapidly at Apache, there are additional differences between the JSP and Servlet implementations in the J2EE SDK and in Tomcat between J2EE SDK releases. Tomcat source and binary code is governed by the ASF license, which freely allows deployment and redistribution.