1.4. Why a Standard Based on Java Technologies?

The market for the Java programming language and its related technologies has grown to nearly two million developers in the years since the Java Development Kit was first released on the Web. Implementations of the Java programming language are now available on desktop systems, servers and mainframes, and in cell phones, personal digital assistants, and other devices.

The Java programming language has gradually morphed from an interesting way to animate static Web pages to a sophisticated platform for producing world-class Web-based applications. While the development of server-side Java technologies may have seemed highly ambitious at one time, server product vendors have shown increasing interest in the technology, and application developers have readily adopted each new server-side Java technology as it was introduced.

Java technology on the server started simply enough with JDBC. This technology allowed clients written in the Java programming language to access server-side databases using standard Application Programming Interfaces (APIs). Java Servlets were the first server-specific technology for the Web, designed to replace Common Gateway Interface (CGI) programs written in a platform-dependent way with a technology that offered the “Write Once, Run Anywhere”™ capabilities of Java technology.

JavaBeans technology paved the way for a component model based on the Java language. Beans provided portable, reusable chunks of functionality, with well-defined interfaces that could play together easily with relatively little additional programming. Java Remote Method Invocation (RMI) enabled applications running in different processes on different machines to communicate with one another in a way that preserved the object-oriented paradigm, thus simplifying the development of distributed applications in the Java language. As the portfolio of Java technologies for supporting enterprise-scale distributed applications grew, so did the interest in presenting them together as a single platform with a unified programming model.

Enterprise JavaBeans (EJB) was the first technology to present the possibility that all these technologies could work together in a unified application model. Designed to simplify the development of transactional business logic, EJB defined a component model in which services such as transaction processing and database access were managed automatically, thus freeing the component developer to focus on the business model of the application. The momentum generated by the EJB model ultimately led to the development of the Java 2 Platform, Enterprise Edition, a complete platform for supporting component-based, distributed enterprise applications.

By providing a component-based solution in which certain services are provided automatically, the J2EE standard commoditizes expertise. The programming expertise required to create sophisticated multitier applications is largely built into the platform, as well as into platform-compatible offerings in the areas of standardized components, automated tools, and other products. This simplifies the programming model, makes expertise available to all, and enables application developers to focus on application-specific technologies.