code: public static String toJSON(List<CustomManifest> list) {
          String output = null;
          if (list != null && !list.isEmpty()) {
              StringBuffer sb = new StringBuffer("[");
              boolean first = true;
              for (CustomManifest cm : list) {
                  if (first) {
                      first = false;
                  } else {
                      sb.append(",");
                  }
                  sb.append(toJSON(cm));
              }
              sb.append("]");
              output = sb.toString();
          }
          return output;
      }
docs: Return the JSON object of the feature information.
  the format is {"name":"custom","featurename":<feature name>, "description": <description>}