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
    the listenablefuture artifact or manually forcing their build systems to
    use 9999.0-....
  </description>
  <build>
    <plugins>
      <plugin>

    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
    the listenablefuture artifact or manually forcing their build systems to
    use 9999.0-....
  </description>
  <build>
    <plugins>
      <plugin>

              [INFO] Validating units:
              [INFO]    Ignored 53 units with compilation errors in first pass.
              [INFO] Compile with -strict or with -logLevel set to TRACE or DEBUG to see all errors.

            Turning up the log level, we see that GWT is trying to compile classes from other
            packages, like RangeTest. The reason for this is that GWT doesn't distinguish between

                <!-- TODO(cpovirk): Use .mvn/jvm.config instead (per
                     https://errorprone.info/docs/installation#maven) if it can
                     be made not to interfere with JDK8 or if we stop building
                     with JDK8. -->
                <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED</arg>

                <!-- TODO(cpovirk): Use .mvn/jvm.config instead (per
                     https://errorprone.info/docs/installation#maven) if it can
                     be made not to interfere with JDK8 or if we stop building
                     with JDK8. -->
                <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED</arg>