Java API for XML-Based Web Services (JAX-WS) – JSR 224 | Download spec
The Java API for XML Web Services (JAX-WS) is the centerpiece of a newly rearchitected API stack for Web services, the so-called "integrated stack" that includes JAX-WS 2.0, JAXB 2.0, and SAAJ 1.3. The integrated stack represents a logical rearchitecture of Web services functionality in the Java WSDP. JAX-WS is designed to take the place of JAX-RPC in Web services and Web applications.
Java Architecture for XML Binding (JAXB) – JSR 222 | Download spec
Java Architecture for XML Binding (JAXB) provides a convenient way to bind an XML schema to a representation in Java code. This makes it easy for you to incorporate XML data and processing functions in applications based on Java technology without having to know much about XML itself.
Streaming API for XML (StAX) (in Java SE) – JSR 173 | Download spec
Streaming API for XML (StAX) is streaming Java-based, event-driven, pull-parsing API for reading and writing XML documents. StAX enables you to create bidrectional XML parsers that are fast, relatively easy to program, and have a light memory footprint.