protected PdxInstance convert(final String json) {
    try {
      return (StringUtils.hasText(json) ? JSONFormatter.fromJSON(json) : null);
    } catch (JSONFormatterException jpe) {
      throw new MalformedJsonException("Json doc specified is either not supported or invalid!",
          jpe);
    }
  }
AbstractBaseController class contains common functionalities required for other controllers.

@since GemFire 8.0
geode-web-api/src/main/java/org/apache/geode/rest/internal/web/controllers/AbstractBaseController.java