In a research project, we analyzed the build file of repositories looking for comments with ready-to-be-addressed SATDs (self-admitted technical debt) that could be addressed. If the underlying issue is already resolved, the related code or comment can be removed or fixed. As we found an instance of this kind of asynchrony in kie-pmml/pom.xml, we decided to report the issue to contribute community.

A comment in drools-core/pom.xml file claims that it is workaround for 
https://github.com/mojohaus/jaxb2-maven-plugin/issues/43, and this issue has been closed long ago.

<!-- TODO: This is a temporary workaround until org.codehaus.mojo:jaxb2-maven-plugin supports JDK9.
(https://github.com/mojohaus/jaxb2-maven-plugin/issues/43). We need to add the plugin back
once we are sure it works on both JDK8 and JDK9.
Using xjc directly (instead of jaxb2-maven-plugin) to support both JDK8 and JDK9 with single configuration.
See https://issues.jboss.org/browse/DROOLS-1170 for more info. -->

Comment location: https://github.com/kiegroup/drools/blob/a8507fae382ec5d815cce03792aa18b0020a1915/kie-pmml/pom.xml#L171-L175