by Janice J. Heiss

With the September 27th Beta release of the Java^TM 2 Platform, Enterprise Edition (J2EE), developers now have access to a complete development platform specifically architected to meet the needs of enterprise application development. J2EE makes all Java enterprise APIs and functionality available and accessible in a well integrated fashion, simplifying complex problems in the development, deployment, and management of multi-tier server-centric enterprise solutions. The J2EE platform exemplifies two familiar Java technology findings: (1) Open standards are better than closed, and (2) "Write Once, Run Anywhere^TM" beats proprietary vendor-lock every time.

This J2EE release offers a Platform Specification, Reference Implementation, Compatibility Test Suite and Application Programming Model. The J2EE Application Programming Model introduces a whole new level of simplified enterprise development by recommending a set of architectural guidelines for developers of distributed enterprise solutions.

"J2EE platform simplifies life for enterprise developers and IT managers through portable, re-usable software components," observes Rick Saletta, senior product marketing manager for the J2EE platform. "J2EE is an architecture rather than a product. It makes solutions possible. J2EE technology accelerates the growth of a competitive, compatible application market, built on the Enterprise JavaBeans^TM component architecture. It is an architecture that embodies a way of thinking about the future. The J2EE platform is scalable, secure, and flexible."

J2EE Platform and Enterprise Computing Solutions

As the Internet and enterprise computing have taken off in the last decade, HTTP, HTML, and the Java platform have emerged as standards for client-based computing, resulting in the development of centralized business logic on the server, and the spread of ecommerce. Myriad programming and connectivity models, like CGI, NSAPI, and ISAPI became prevalent. Web servers tended to reduce access between the browser-based client and each individual enterprise application, causing programming and maintenance nightmares. More recently, application servers have enabled the aggregation of enterprise services into a web-facing display, which has simplified the programming of multiple enterprise applications.

The existence of over 25 application servers on the market, each with product-specific programming models which lock the application builder into one specific product or platform, constitutes a major obstacle to innovation. Applications written to one server are locked into the server architecture, and unable to take advantage of fast-developing features and performance enhancements in the industry. To innovate, developers have been faced with the expensive proposition of creating an entirely new application model, which usually involves rewriting the application to a new server with the desired features and enhancements.

Java 2 Platform: Editions for business solutions

No More Vendor-Lock

Such an industry-wide predicament calls for a solution: the creation of a single, unified platform with an easy-to-use model for building applications that enables ecommerce in a distributed computing environment across a wide array of products. The J2EE platform offers that solution. "J2EE technology enables faster solution delivery time to market for enterprise developers," comments Saletta. "On the Web, that means everything. Vendors need to have flexibility -- they cannot afford to be locked into inferior solutions. Enterprises doing business on the Web, can in a matter of days, lose market share it took years to accrue."

1. Simplified Enterprise Development. J2EE platform offers system vendors the ability to provide a solution that brings together multiple types of middleware in one product, eliminating the time and expense of getting different pieces of server software to talk to each other. J2EE platform allows system vendors to create an environment containing the various pieces of server software, such as database, transaction, and naming services, in one environment.

2. Industrial Strength Scalability. J2EE platform offers the full scalability necessary in the enterprise, where applications often scale from small working prototypes and test cases to complete 24 X 7 enterprise-wide services, accessible by thousands of clients.

3. Legacy Connectivity. J2EE platform enables the ISV to layer this platform on top of their existing products, preserving their investment in technology.

4. Open Platform (choice/flexibility). J2EE platform is an open standard. Sun is committed to working with technology partners to ensure an open process for the platform direction, specifications, reference implementations and compatibility.

5. Security. J2EE platform offers a security model that protects data in Internet applications.

6. Portability - "Write Once, Run Anywhere". J2EE platform allows for innovation without disturbing the ISV's enterprise solutions and investment. J2EE technology provides a set of interfaces to a platform, while the ISV delivers the implementation. If an ISV wants to use a new and improved piece of its system software, like a new transaction server, the old server can be removed, and the new one added to the J2EE technology-enabled server. The end-user's code is not disturbed.

J2EE Platform: The Whole is Greater than the Sum of its Parts

J2EE platform represents not only a step forward in Java technology's evolution, but illustrates an organizational principle that informs Sun's existing technologies. During its first year, the Java^TM 2 Standard Edition (or Java^TM Developer Kit) was applied to a broad range of products and solutions ranging from hand-held devices to server solutions. Initial feedback from customers pointed to the need for market APIs. In its second year, Sun made available market-specific APIs and technologies for vertical markets, and began to develop specifications for a target set of APIs and technologies that would meet the enterprise needs of the IT developer. This included technology like the JDBC^TM data access API.

Next, Sun began to deliver platforms to specific market segments, including EmbeddedJava^TM and PersonalJava^TM platforms. In addition, Sun offered cornerstone technologies for the enterprise platform like the Enterprise JavaBeans architecture and the Java Messenger Service API.

Sun has a number of "point technologies" that solve specific problems. Enterprise JavaBeans technology provides a component model for server-side computing. Servlets offer a mechanism for writing web server extensions once, and having them run on a server. JavaServer Pages^TM (JSP) technology allows web page designers to do server-side scripting in the Java programming language. "JSP technology is the easiest way to create dynamic web pages," observes Saletta. "it connects web content to the enterprise."

The JDBC^TM API allows for consistent database access across a wide range of products on the Java platform. While each technology is valuable in and of itself, in bringing them together in one platform, the whole is greater than the sum of its parts.

Java 2 Enterprise Edition: The Sum of its Parts

As a complete computing environment, a platform supplies many integral components. In sum, there are four major parts: Platform Specification, Reference Implementation (RI), Compatibility Test Suite, and Application Programming Model.

Here are the deliverables that are part of the Java 2 Platform, Enterprise Edition:

1. The Platform Specification lists the required elements of the platform, plus the policies that must be followed for a valid J2EE implementation.

2. The Reference Implementation is a prototype that provides a semantically correct instance of J2EE platform for vendors to test against. The RI validates the specifications, speeds development time, acts as a debugging tool, and functions as a tool for passing compatibility tests. The source code for the RI (available in December) serves as an example of how to implement a valid version of the platform. The RI includes: tools for deployment and system administration, EJBs, JSPs, a container with deployment and runtime support, and support for transaction management, Java Messaging Service, Mail, Connectors and 3rd party products.

3. The Compatibility Test Suite consists of three components. The first tests for basic API-level compatibility through method signature testing, and tests to make sure the APIs in the implementation are neither a superset nor a subset of the required set of APIs. The second component includes a set of tests to make sure the individual components work properly. A third part tests for end-to-end compatibility, and focuses on the product's use of the technologies in an effort to mandate a minimum level of functionality across all tiers of the J2EE environment.

4. The Application Programming Model (APM) consists of a best practices philosophy for the design and building of J2EE technology-based applications. The APM, which offers unprecedented simplicity developing to a platform, walks developers through the do's and don'ts of the J2EE platform. The APM provides the philosophy for building multi-tier applications on the J2EE platform. It offers a set of design patterns for designing such applications, as well as a set of examples or recipes for building them. The APM addresses such issues as achieving industrial strength scalability, legacy connectivity, and enterprise security. "The Java 2 Platform, Enterprise Edition, Application Programming Model enables faster product delivery time to market for enterprise developers," notes Saletta.

The first 8 to 10 chapters of the APM are now available. Sun strongly encourages developers to download and read the available chapters. "We are very eager for developer feedback," says Saletta. "The chapters contain a sample application with both binary and source code that shows how to set up and architect an E-store, using the J2EE platform. We want folks to modify it and build with it and give us their feedback." Chapters from the APM can be downloaded from http://java.sun.com/j2ee.

The Three Cs: Components, Containers, Connectors

J2EE APM divides enterprise applications into three fundamental parts: components, containers, and connectors.

Components. The APM enables the development of component solutions by providing three core technologies for building enterprise applications. First, Enterprise JavaBeans components enable the construction of server-side solutions that can be built without regard for the database, transaction server, or application it runs on. Second, servlets enable the construction of high-performance web services that can run on the vast majority of web servers in the market. Third, JavaServer Pages technology allow for the construction of dynamic content that leverages off the full power of the Java programming language.

Containers. J2EE APM enables the construction of containers that provide high-performance, scalable environments for J2EE technology-enabled servers that support Enterprise JavaBeans technology-based components (enterprise beans), servlets and JavaServer Pages technology-based pages.

Connectors. Finally, the APM enables the construction of connectors that allow J2EE technology-based solutions to preserve, protect and leverage off of existing enterprise investments.

Unifying the Three Cs

The J2EE platform unifies the three Cs into one platform with a standard, platform-independent technology that replaces proprietary code. It thus provides an architecture that allows server-centric components, and is able to run in any J2EE technology container, and interoperate via connectors with a broad range of existing services in the enterprise. This translates to applications built with components that can be run on any J2EE technology-enabled server, and able to talk to the enterprise-class systems that exist in data centers today.

J2EE Platform Supports XML

The J2EE platform fully supports and implements the XML standard. "To say that XML is competitive with Java technology could not be further from the truth," explains Saletta. "J2EE and XML technologies are the Yin and Yang of enterprise development. XML enables platform independent data. J2EE platform enables platform independent solutions -- and it supports XML completely."

Looking Ahead

First customer shipping of the J2EE platform is scheduled for December. Down the road, Sun will be coming out with a set of products, services, and educational tools that complement the J2EE platform and support enterprise developers in their endeavors. Already, J2EE technology has received over 60 endorsements as Sun's partners begin building solutions and tools based on the J2EE reference implementation.

"Through the Java Community Process, Sun has successfully created a compatible, competitive market for J2EE components and solutions," comments Saletta. "Based on widely accepted standards, J2EE technology will accelerate the pace of innovation in the enterprise, resulting in faster time to market for strategic enterprise solutions."

Distribution Information

A binary of the Reference Implementation is currently available for the Java 2 Platform, Enterprise Edition, along with the first 8 to 10 chapters of the APM. J2EE source code will be available in December under the Sun Community Licensing Program.

Download Java 2 SDK, Enterprise Edition, Beta Release
(http://developer.java.sun.com/developer/earlyAccess/j2sdkee)

See Also

Java^TM 2 Platform, Enterprise Edition (J2EE) Home Page
(http://java.sun.com/j2ee/)

[ This page was updated: 28-Sep-99 ]