docs: private static String getJsonValue(JsonValue value) {
          String s = null;
          if (value != null) {
              s = getJsonValueAsString(value);
              if (s == null) {
                  s = getJsonValueAsNumberString(value);
              }
              if (s == null) {
                  Boolean b = getJsonValueAsBoolean(value);
                  if (b != null) {
                      s = b ? "true" : "false";
                  }
              }
          }
          return s;
      }