Copied from BZ:

The FSW installation includes a soa module, 'org.apache.xmlgraphics'. This module includes two jars that deal with XML APIs. (The two are 'xml-apis-1.3.04.jar' and 'xml-apis-ext-1.3.04.jar').

A user has reported a linkage error where conflicting versions of one of the XML API classes are clashing.

It seems these APIs (v4) are included with the JDK.

A usable workaround is also the suggested long term fix:

Edit modules/system/layers/soa/org/apache/xmlgraphics/main/module.xml
Remove the xml-apis jar as a resource root
<!--
<resource-root path="xml-apis-1.3.04.jar" />
-->

and add export="true" to javax.api dependency.

<module name="javax.api" export="true"/>