Support for web services in EJB 2.1 is based on the web services for the J2EE 1.1 (WS-J2EE) specification. This specification includes the Java API for XML-based RPC (JAX-RPC), SOAP with Attachments API for Java (SAAJ), and the Java API for XML Registries (JAXR). JAX-RPC is basically Java RMI over SOAP; SAAJ is an API for manipulating the structure of a SOAP message; and JAXR allows you to access web service registries, usually UDDI (Universal Description, Discovery and Integration).
While this chapter and the one before it provide you with a launching pad for learning about web services in J2EE (specifically EJB), the subject is too huge to cover in a book about EJB. In order to cover J2EE web services comprehensively we would have needed another 500 pages—since you’ll need to lift this book to read it, I wrote a lighter approach to the subject. This chapter provides you with an introduction to JAX-RPC, but it should not be considered a comprehensive guide to the API.
If you are interested in learning more about the standard web services technologies (XML, SOAP 1.1, WSDL, and UDDI) and J2EE APIs (JAX-RPC, SAAJ, and JAXR), you might want to read J2EE Web Services (Addison-Wesley) by the author of this book, for a complete and thorough coverage of these topics.
The main purpose of JAX-RPC is to describe the relationship between WSDL 1.1, XML, SOAP 1.1, and Java. JAX-RPC provides EJB with a client-side programming model for accessing remote web services, ...