code: public static void removeIndexData(ValidationData data, ValidationDataIndex index) {
  
          String key = index.getKey(data);
          List<ValidationData> datas = index.get(key);
  
          if (!datas.isEmpty()) {
              datas = datas.stream().filter(d -> !d.getId().equals(data.getId())).collect(Collectors.toList());
          }
          if (datas.isEmpty()) {
              index.getMap().remove(key);
          } else {
              index.getMap().put(key, datas);
          }
      }
docs: Remove index data.
  
  @param data  the data
  @param index the index