News

Explaining Java and Web services

• By John K. Waters
• April 9, 2002

One of the biggest problems with Web services, said David Chappell and Tyler Jewell, is explaining it -- that is, pulling all the pieces together into a coherent and hype-free description of what Web services are and how developers can create and deploy them. Longtime developers Chappell and Jewell are most concerned with Java jocks, and their solution is a new book, Java Web Services (O'Reilly).

"Dave and I recognized that the Java community had a strong need to understand how Java applications exist in a Web services world," said Jewell. "Web services are key for doing application integration, but what does that mean for those applications that are built using Java? We tried to answer that question in this book."

Chappell and Jewell provide readers with a concise introduction that includes a detailed overview of Web services, XML-based interoperability technologies and the Java technologies designed to interact with them. According to sources at this year's JavaOne conference, where the book made its debut, the authors assembled the manuscript in record time under pressure from the publisher to make the show. But the book doesn't seem at all rushed, and at 254 pages, the authors manage to meet their objectives.

Readers can find working examples of how each Java-based API can be used in real-world, business-to-business communications environments. The authors explain how Java developers can use SOAP to perform remote method calls and message passing; how to use WSDL to describe the interface to a Web service or understand the interface of someone else's service; and how to use UDDI to advertise, or publish and look up services in each local or global registry.

The book also covers security and interoperability issues; integration with other Java enterprise technologies, such as EJB and JMS; the work being done on JAXM and JAX-RPC packages; and even interoperability with Microsoft's .NET services.

"There is a great deal of hype and confusion out there about how Web services technology can be used," said Chappell. "With myriad evolving standards and technologies -- some real and some not yet baked -- we felt it was important to do the investigative work to determine what's viable now and what needs to mature. We believe our book provides some real-world clarity."

Both Jewell and Chappell are ink-stained veterans of technology book publishing. Jewell is director of technical evangelism at BEA Systems, where he oversees that company's efforts to encourage early adoption of strategic BEA technologies by the ISV and developer community. A technologist with expertise in Web services, large-scale system design and application infrastructures, he is the author of Mastering Enterprise JavaBeans 2.0 (Wiley, 2001) and Professional Java Server Programming J2EE 1.3 (Wrox, 2001).

Chappell (who is not related to ADT's columnist of the same name) is vice president and chief technology evangelist at Sonic Software. He has been building software tools and infrastructure for application developers for more than 18 years, and oversaw the design and development of the first commercial implementation of JMS in the marketplace. Chappell is co-author of Java Message Service (O'Reilly) and Professional ebXML Foundations (Wrox).

The publishers are making Chapter 6, "UDDI: Universal Description, Discovery and Integration" available free online at http://www.oreilly.com/catalog/javawebserv/chapter/ch06.html.