GWT happens to use the prod .gwt.xml, so it looks for no supersource for
    tests, either. This causes it to fail to find AtomicLongMapTest.

    Our workaround is to tell GWT that util.concurrent and all other packages
    have prod supersource, even if they have none. GWT is happy to ignore us
    when we specify a nonexistent path.

        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
          <excludes>
            <!-- Yes, we want to exclude ForceGuavaCompilation 4 times: -->
            <!-- (And we might as well exclude DummyJavadocClass 3 times (though it would be harmless to include).) -->
            <!-- 1. Don't compile it (since that requires a *non-test* dep on gwt-user. -->
            <exclude>**/ForceGuavaCompilation*</exclude>

    GWT happens to use the prod .gwt.xml, so it looks for no supersource for
    tests, either. This causes it to fail to find AtomicLongMapTest.

    Our workaround is to tell GWT that util.concurrent and all other packages
    have prod supersource, even if they have none. GWT is happy to ignore us
    when we specify a nonexistent path.

          <version>3.0.0+</version>
          <required>true</required>
          <description>The year of the project's inception, specified with 4 digits. This value is
            used when generating copyright notices as well as being informational.</description>
          <type>String</type>
        </field>
        <field>
          <name>organization</name>
          <version>3.0.0+</version>

        then the existence of the named property will activate the profile, otherwise it does a case-sensitive
        match against the property value as well.
      ]]></description>
      <fields>
        <field>
          <name>name</name>
          <version>1.0.0</version>
          <type>String</type>
          <required>true</required>

        then the existence of the named property will activate the profile, otherwise it does a case-sensitive
        match against the property value as well.
      </description>
      <fields>
        <field>
          <name>name</name>
          <version>1.0.0+</version>
          <type>String</type>
          <required>true</required>
          <description>