xml parsing

[Alex Kleider <akleider@sonic.net>]

As a new comer to DocBook I've bee using the following tool chain:

jing /usr/share/xml/docbook/schema/rng/5.0/docbook.rng 
docbookDocument.xml
xmlto --skip-validation html bluebook.xml

It seems to work, but:

From my reading:
DocBook.xml must first be checked for XML parsing errors before it is
validated against docbook.rng (RelaxNG grammer and Schematron rules.)
Jing is a RelaxNG validator (in Java.)

Does Jing also check xml parsing errors or should I be using another 
tool first?
I can't find clarification of this issue on the Jing site (or anywhere 
else, for that matter.)

I've been using vim as my editor, on a Linux (Ubuntu) platform.

Any advice/guidance appreciated.
Thanks.

alex