Web services enable the new generation of Internet-based applications. These services support application-to-application Internet communication-that is, applications at different network locations can be integrated to function as if they were part of a single, large software system. Examples of applications made possible by Web services include automated business transactions and direct (nonbrowser) desktop and handheld device access to reservations, stock trading, and order-tracking systems.Several key standards have emerged that together form the foundation for Web services: XML (Extensible Markup Language), WSDL (Web Services Definition Language), SOAP (Simple Object Access Protocol), and UDDI (Universal Description, Discovery, and Integration). In addition, ebXML (Electronic Business XML) has been specified to facilitate automated business process integration among trading partners.This book introduces the main ideas and concepts behind core and extended Web services' technologies and provides developers with a primer for each of the major technologies that have emerged in this space. In addition, Understanding Web Services summarizes the major architectural approaches to Web services, examines the role of Web services within the .NET and J2EE communities, and provides information about major product offerings from BEA, Hewlett-Packard, IBM, IONA, Microsoft, Oracle, Sun Microsystems, and others.Key topics include:XML facilities for structuring and serializing data How WSDL maps services onto communication protocols and transports WSDL support for RPC-orientedand document-oriented interactions SOAP's required and optional elements Message processing and the role of intermediaries in SOAPUDDI data formats and APIsHow ebXML offers an alternative to Web services that supports reliable messaging, security, and trading-partner negotiationsWith Understanding Web Services, you will be well informed and well positioned to participate in this vast, emerging marketplace.