public java.util.List<? extends org.box2d.proto.Box2D.PbFixtureOrBuilder> 
           getFixturesOrBuilderList() {
        if (fixturesBuilder_ != null) {
          return fixturesBuilder_.getMessageOrBuilderList();
        } else {
          return java.util.Collections.unmodifiableList(fixtures_);
        }
      }