In a jigsaw changeset [1], configuration files were moved from ${java.home}/lib directory to ${java.home}/conf. However, two of them were missed.
javax/xml/stream/FactoryFinder.java:
There were two references to the "lib" directories. The one for jaxp.properties was replaced with "conf", but the other for stax.properties was missed.
javax/xml/xpath/XPathFactoryFinder.java:
The jigsaw changeset contained the correct change. However, the change is not in the current JDK 9/jaxp repository. It could have been a glitch in the source merge.
Note that a follow-up spec change for jigsaw was documented through JDK-8049378.
[1] http://hg.openjdk.java.net/jigsaw/m2/jaxp/rev/b7027b4b5c06