Section I: Introduction to Web Service Technologies

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Overview

Microsoft, IBM, and Sun Microsystems are all pushing Web Services as the next great technology to allow developers to create remote objects easily. Earlier remote object technologies, such as COM+ and CORBA, were difficult to implement and had high maintenance costs. Additionally, in the case of CORBA, it was expensive to purchase the operational license. The promise of Web Services is to finally make remote objects a reality, but many of the details, such as security, seem to be hidden or spread across several different Web sites. Plus the term Web Services is generic and doesn’t hint at all the underlying technologies. This chapter describes at a high level the tool and standards that make Web Services possible and the related technologies.

Web Services encapsulate Remote Procedure Call (RPC) with XML as the data packaging. The design of Web Services considers the pitfalls of the aforementioned remote object technologies and tries to avoid them. Although the use of Web Services does solve many of the problems, it also creates many new problems. Such problems are discussed throughout the book.

But before jumping into Web Services, it is important that you understand several basic concepts such as objects, libraries, classes, remote objects, and the like. By understanding these basic ideas, the evolution of Web services will make more sense, and you’ll begin to see why the use of Web services has moved to the forefront of Web technology.