String encode(String value) {
    if (value == null) {
      throw new GemfireRestException("could not process null value specified in query String");
    }
    return encode(value, DEFAULT_ENCODING);
  }
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