Try JDOM

if you want to "browse" your xml document you need to use a DOM api.
you can find an implementation here http://xerces.apache.org/xerces-j/

the drawback of this method is that you load the whole document in
memory and that the initial parsing is (relativly) slow.

an other option is to parse the document as a stream; known as SAX.
there is a SAX parser (crimson) embedeed in the Sun JRE.

unsing SAX, if you want to validate before loading, you have to parse
twice (ugly!), if not, you can validate and load data at the same time
but your process could fail before the end of the file (maybe unsafe).
I advise you to do it in one pass with a same way to fail using a
temporary Map and not the main one.
<code>mainMap.putAll(tmpMap)</code>

see http://mindprod.com/jgloss/xml.html

The Java code to validate with an XSD schema is trivial.