SAX, the Simple API for XML
DOM, the Document Object Model
DOM Level 0
DOM Level 1
DOM Level 2
Parser specific APIs
Sun's Java API for XML Parsing = SAX1 + DOM1 + a few factory classes
JSR-000031 XML Data Binding Specification from Bluestone, Sun, webMethods et al.
The proposed specification will define an XML data-binding facility for the JavaTM Platform. Such a facility compiles an XML schema into one or more Java classes. These automatically-generated classes handle the translation between XML documents that follow the schema and interrelated instances of the derived classes. They also ensure that the constraints expressed in the schema are maintained as instances of the classes are manipulated.