code: private static Map<String, Object> convert(
          final Map<CharSequence, Object> params) {
          final Map<String, Object> map = new HashMap<>(params.size());
          for (final Map.Entry<CharSequence, Object> ent : params.entrySet()) {
              map.put(ent.getKey().toString(), ent.getValue());
          }
          return map;
      }
docs: Converts Map of CharSequence, Object to Map of String, Object.
  @param params Parameters in Map of CharSequence, Object
  @return Map of String, Object.