public List<ValidationData> findByParentId(Long id) {
        return this.datas.stream().filter(d -> d.getParentId() != null && d.getParentId().equals(id)).collect(Collectors.toList());
    }
public List < ValidationData > findByParentId ( Long id ) { return this . datas . stream ( ) . filter ( d -> d . getParentId ( ) != null && d . getParentId ( ) . equals ( id ) ) . collect ( Collectors . toList ( ) ) ; }
Find by parent id list.

@param id the id
@return the list