version number is enough for some build systems (notably, Gradle) to select
    that empty artifact over the "real" listenablefuture-1.0 -- avoiding a
    conflict with the copy of ListenableFuture in guava itself. If users are
    using an older version of Guava or a build system other than Gradle, they
    may see class conflicts. If so, they can solve them by manually excluding

      <groupId>com.google.guava</groupId>
      <artifactId>guava</artifactId>
      <version>${project.version}</version>
    </dependency>
    <!-- We redeclare the j2objc-annotations dependency from `guava`: Our Gradle
         Module Metadata hides the dependency declared in `guava` from runtime
         configurations downstream, and GWT uses the runtime configuration for