JAXP (JSR-206) in a nutshell

JAXP(JSR-206) covers following specifications:

• DOM (org.w3c.dom package)
• SAX (org.xml.sax package)
• StAX/JSR-173 (java.xml.stream)
• XSLT (javax.xml.transform)
• XPath (javax.xml.xpath)
• Validation (javax.xml.validation)
• Datatypes (javax.xml.datatype)

Implemetations:

Xerces - Is an open source Java XML parser that provides DOM and SAX implementations that are compliant with the JAXP standard.

JDOM and DOM4J - Are open source Java XML parsers.