The Challenges of Developing Enterprise Applications

Enterprise applications are facing many challenges, such as portability, reusability, interoperability, and application integration. Since the inception of Java in 1995 as a simple object-oriented and portable language, its main focus was on the development of portable client-side applications. The challenges of developing portable Java enterprise applications remain due to the lack of server-side application development framework and tools. By server-side computing, we imply the design of small, location-transparent components that work together to fulfill enterprise service requirements. In many cases, these lightweight components can work as both client and server.

Enterprise computing is rapidly changing in both hardware and software. New applications are required to meet with the emerging user demands, and are still required to interface with existing applications. It's not practical to throw out the huge investment in applications written in older-generation languages that already work to maintain data in legacy systems. This dictates a need to integrate new applications with the existing systems. Today, server-side software offers the corporate world many opportunities to rethink its enterprise-wide computing infrastructure. With the acceptance and growth of Java in recent years, software portability, reuse, and application integration have become important and accepted for many client applications spread throughout the enterprise.

Enterprise applications are complex, and in many cases require the development of several teams, which might span multiple domains. Today's applications are required to have faster time to market to compete and to fulfill user demands. Another challenge facing the enterprise is interoperability with other environments, which might be heterogeneous in hardware, software, or network architectures.

In facing such challenges, enterprise application architectures have undergone an extensive evolution. The first generation of enterprise applications was centralized mainframe applications. In the late 1980s and early 1990s, most new enterprise applications followed a two-tier architecture approach (also known as the client/server architecture). Later, the enterprise architecture evolved to a three-tier, and then to a Web-based architecture.

One of the solutions for these challenges is the J2EE technology, which was developed by Sun Microsystems. The following sections describe the J2EE architecture and, as a major participant, the EJB technology of developing component-based enterprise applications.