worked everywhere that I know of except for one place: when running the GWT
    util.concurrent tests under Guava.

    The problem is that GWT responds poorly to two .gwt.xml files in the same
    Java package; see https://goo.gl/pRV3Yn for details.

    The summary is that it ignores one file in favor of the other.
    util.concurrent, like nearly all our packages, has two .gwt.xml files: one

    worked everywhere that I know of except for one place: when running the GWT
    util.concurrent tests under Guava.

    The problem is that GWT responds poorly to two .gwt.xml files in the same
    Java package; see https://goo.gl/pRV3Yn for details.

    The summary is that it ignores one file in favor of the other.
    util.concurrent, like nearly all our packages, has two .gwt.xml files: one

                   builds with JDK8 began failing animal-sniffer with the error:

                   Failed to check signatures: Bad class file .../CollectionFuture$ListFuture.class

                   One way of dealing with that would be to disable
                   animal-sniffer. And that would be fine for our -jre builds:
                   If we're building with JDK8, then clearly we're sticking to

          <!-- Note that we do need to build Javadoc for *some* class. Otherwise, we get an empty Javadoc jar, which the Sonatype repository manager rejects. To avoid that, we've introduced a dummy class. But we made it package-private so that no one can depend on it. That in turn forced us to configure Javadoc to show package-private APIs. -->
          <show>package</show>
        </configuration>
      </plugin>