I think the best approach for xml  based binding  is JAXB. Using JAXB, u can
perform marshalling and unmarshalling of data  in XML files. so u can use JAXB
api's and convert xml file data into java  classes instances (marshalling), then
do whatever u wanna do with it and finally convert java class instances into xml
files(unmarshalling). I know SAX, DOM, JAXP all work to this.. but beleive me,
nothing is simpler than JAXB.