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

    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
    for prod and one for tests. However, unlike our other packages, as of this

    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
    for prod and one for tests. However, unlike our other packages, as of this

    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
    for prod and one for tests. However, unlike our other packages, as of this

    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
    for prod and one for tests. However, unlike our other packages, as of this

            <goals>
              <goal>attach-artifact</goal>
            </goals>
            <configuration>
              <artifacts>
                <artifact>
                  <file>target/publish/module.json</file>
                  <type>module</type>
                </artifact>
              </artifacts>
            </configuration>
          </execution>
        </executions>
      </plugin>

    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
    for prod and one for tests. However, unlike our other packages, as of this

    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
    for prod and one for tests. However, unlike our other packages, as of this

    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
    for prod and one for tests. However, unlike our other packages, as of this

    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
    for prod and one for tests. However, unlike our other packages, as of this