code: public void setCustomTickmarkLabels(final double... CUSTOM_TICKMARK_LABELS_ARRAY) {
          customTickmarkLabels.clear();
          for (Double label : CUSTOM_TICKMARK_LABELS_ARRAY) {
              customTickmarkLabels.add(label);
          }
          reInitialize();
      }
docs: Takes a array of doubles that will be used as custom tickmark labels
  e.g. you only want to show "0, 10, 50, 100" in your
  gauge scale so you could set the custom tickmarklabels
  to these values.
  @param CUSTOM_TICKMARK_LABELS_ARRAY