We were able to resolve this issue by following the suggestion posted in this github link

https://github.com/bjornvester/wsdl2java-gradle-plugin/issues/26 

We forked this code and then compiled using the dependency

• jaxb-xjc: 4.0.5
• jaxb-core: 3.0.2

Under PluginImpl the import statement was replaced with

• import org.glassfish.jaxb.core.api.impl.NameConverter; and also NameConverter was casted as follows

NameConverter nc = (NameConverter) context.parent().getModel().getNameConverter();

With the following changes, we published the plugin code to our local repo and use this plugin in cxf-codegen-plugin

I shall commit the code sample shortly for reference

Thanks -Raghavan