Java Web Services
At the end of the day, Web services aren't hard to conceptualize. They're just a bunch of software modules with specific rules about how they go about discovering one another and sending messages back and forth. Implementation is another story, however. In the Java language, writing Web services requires an understanding of half a dozen specialized APIs at minimum, and more than that if you want to do fancier stuff.Java Web Servicesdoes a very good job of dispersing the confusing terminology (and obfuscating hype) and of showing you exactly how todoWeb services work in Java. This doesn't sound like a revolutionary concept, but unfortunately it is. David Chappell and Tyler Jewell have comfortably fit into less than 250 pages what others have not done as well in twice as much space.Take Universal Description, Discovery, and Integration (UDDI) work as an example. UDDI exists to help software locate other software that does what it wants. How do you do that? Chappell and Jewell present two concise program listings--a client and a server--that show how to do a  UDDI lookup. They then refine their code by using a third-party API that makes the work easier. Similarly pragmatic attention goes to Simple Object Access Protocol (SOAP), in which they show how to create a message, populate it with XML, make an attachment if necessary, and send it on its way. You won't find a lot of frills or conceptual explanations (though there are enough "why" sections to ensure that you're not just typing recipes blindly); the emphasis is on writing Java code that interacts with Web services protocols and standards.--David WallTopics covered:How to write Web services software in Java, with respect to Universal Description, Discovery, and Integration (UDDI), Simple Object Access Protocol (SOAP), and Web Services Description Language (WSDL). There's also coverage of interprocess communication under JAX-RPC and ways to implement security. All of the low-level stuff is here. Look elsewhere for architecture and design information.