code: public static Set<Field> getFieldsAnnotatedBy(Class<?> classs, Class<? extends Annotation> ann) {
      Set<Field> set = new HashSet<>();
      for (Field field : getAllFields(classs)) {
        if (field.isAnnotationPresent(ann)) {
          set.add(field);
        }
      }
      return set;
    }
docs: Gets all fields annotated by annotation.
  
  @param classs class to get fields from
  @param ann    annotation that must be present on the field
  @return set of fields