JAXB reference implementation not found?

[dwilcoxen]

I've seen this error discussed here before and have tried to follow what the issue is, but I don't understand:

java.lang.NoClassDefFoundError: com/sun/xml/bind/marshaller/NamespacePrefixMapper

farther down:

org.docx4j.jaxb.NamespacePrefixMapperUtils - JAXB: neither Reference Implementation nor Java 6 implementation present?

How would it not be present if it's running under 8.1? I can see the class in jre/lib/rt.jar

Obviously I'm missing something.

It works fine on my own system but two other developers have reported this error. Their classpath is the same as mine.

[dwilcoxen]

It appears we had a conflict between the "JAXB" feature in Websphere Liberty and docx4j. As configured it was loading libraries from the com.ibm space and they didn't work. After I removed the feature from Liberty, it began loading from rt.jar and works now.