Overview of the Java APIs for XML
The Java APIs for XML let you write your Web applications entirely in the Java programming language. They fall into two broad categories: those that deal directly with processing XML documents and those that deal with procedures.
Java API for XML Processing (JAXP)processes XML documents using various parsers
Java API for XML Messaging (JAXM)sends SOAP messages over the Internet in a standard way
Java API for XML Registries (JAXR)provides a standard way to access business registries and share information
Java API for XML-based RPC (JAX-RPC)sends SOAP method calls to remote parties over the Internet and receives the results
Perhaps the most important feature of the Java APIs for XML is that they all support industry standards, thus ensuring interoperability. Various network interoperability standards groups, such as the World Wide Web Consortium (W3C) and the Organization for the Advancement of Structured Information Standards (OASIS), have been defining standard ways of doing things so that businesses who follow these standards can make their data and applications work together.
Another feature of the Java APIs for XML is that they allow a great deal of flexibility. Users have flexibility in how they use the APIs. For example, JAXP code can use various tools for processing an XML document, and JAXM code can use various messaging protocols on top of SOAP. Implementers have flexibility as well. The Java APIs for XML define strict compatibility requirements to ensure that all implementations deliver the standard functionality, but they also give developers a great deal of freedom to provide implementations tailored to specific uses.
The following sections discuss each of these APIs, giving an overview and a feel for how to use them.