Java API for XML Processing. Includes libraries for SAX and DOM processing of XML documents, as well as support for other XML technologies, such as XSLT and XML schema.
Sun's XML manipulating classes
JAXP or Java API for XML Parsing is an optional API provided by Javasoft. It provides basic functionality for reading, manipulating, and generating XML documents through pure Java APIs. It is a thin and lightweight API that provides a standard way to seamlessly integrate any XML-compliant parser with a Java application. More at http://java.sun.com/xml