code: public static String deepFieldName(Field field) {
  
          DeepField annotation = field.getAnnotation(DeepField.class);
          if (StringUtils.isNotEmpty(annotation.fieldName())) {
              return annotation.fieldName();
          } else {
              return field.getName();
          }
      }
docs: Returns the field name as known by the datastore. If the provided field object DeepField annotation
  specifies the fieldName property, the value of this property will be returned, otherwise the java field name
  will be returned.
  
  @param field the Field object associated to the property for which we want to resolve the name.
  @return the field name.