My application needs to use xerces1.4.4.jar, while Jboss defaults to use xercesImpl.jar. The DOMParser.class is in both of these jars. I've modified my application.xml file for my .ear to look for xerces.1.4.4.jar, or so I've thought. However, when my application runs, I get a NoSuchMethodException on the method setIncludeIgnorableWhitespace. This method is in the xerces.1.4.4 version of the DOMParser, but not in the xercesImpl version, which leads me to believe that jboss is still picking up it's loaded version of the class as opposed to the version I'm intending to be used with my .ear. Could someone give me a hand in figuring out why jboss isn't looking to my .jar file when my ear attempts to use that class? Is there some way to tell my .ear to use that .jar file instead of the jboss xerces file that I'm missing?