</executions>
        </plugin>
        <plugin>
          <artifactId>maven-javadoc-plugin</artifactId>
          <version>3.5.0</version>
          <configuration>
            <quiet>true</quiet>
            <notimestamp>true</notimestamp>
            <encoding>UTF-8</encoding>
            <docencoding>UTF-8</docencoding>
            <charset>UTF-8</charset>
            <additionalOptions>

            <configuration>
              <module>com.google.common.ForceGuavaCompilation</module>
              <failOnError>true</failOnError>
              <logLevel>${gwt.logLevel}</logLevel>
              <generateJsInteropExports>true</generateJsInteropExports>
              <validateOnly>true</validateOnly>
              <sourceLevel>1.8</sourceLevel>
              <!--