TABLE OF CONTENTS Web services represent a new breed of Web-specific software component methodology. They are a new type of object-oriented (OO) programming la the Web. Web services are modular, self-contained, self-describing software components. These software components are available over the Web (i.e., they are published on the Web). They can be readily located and checked out, online and dynamically, using a new directory and corresponding search mechanism known as Universal Description, Discovery, and Integration (UDDI). They are also invoked and consumed (i.e., used) across the Web hence, the term Web services, reflecting the fact that these are software services for application developers that are totally Web-centric.
Web services are truly platform independent. This platform independence, furthermore, applies to both sides of a Web services configuration (i.e., the usage side as well as the provision side). Thus, applications that use Web services can run on any platform. Web services themselves, in turn, are also totally platform independent. There are also no restrictions as to what platforms they can be developed upon. Hence, there are no platform-related restrictions whatsoever as to which Web services can be used by which applications or as to how and where the Web services, or for that matter the applications, were developed. Therefore, it is possible to have a Web application running on a Windows 2000 server that relies on three Web services: one running on a UNIX server from Sun, a second on a Unisys mainframe, and the third on an IBM iSeries...
