In WFLY 25 and jboss-modules 1.x,
respects the META-INF/services from module org.codehaus.woodstox and finally delegates to com.ctc.wstx.stax.WstxOutputFactory to create XMLWriter.
After jboss-modules is upgraded to 2.0 in WFLY 26, it doesn't read the META-INF/services configuration and return the JDK's com.sun.xml.internal.stream.XMLOutputFactoryImpl.
This leads regression failures in jbossws-cxf test suite like :
More test failures log please look at : https://issues.redhat.com/browse/JBWS-4235