Newbie question- Running DOM TS

Hi people,
Please bear with me for asking such a stupid question- when I try to
run the DOM TS against my DOM implementation, it tests the JRE DOM
implementation and not my implementation. This is the message I get:

<snip>
See W3C License http://www.w3.org/Consortium/Legal/ for more details.

Implementation title:Java Runtime Environment
Implementation vendor:Sun Microsystems, Inc.
Implementation version:1.4.2_06
</snip>

 Setup: copied dom3-core-tests-20040405.jar to my DOM implementation
classes directory and ran using java - jar 
dom3-core-tests-20040405.jar

 I went through the FAQs as well as the mail archive but couldnt find
an answer to my question. Any help will be greatly appreciated.
Apologetically yours,
Neo