code: public static Specification<JpaDistributionSet> byId(final Long distid) {
          return (targetRoot, query, cb) -> {
              final Predicate predicate = cb.equal(targetRoot.<Long> get(JpaDistributionSet_.id), distid);
              targetRoot.fetch(JpaDistributionSet_.modules, JoinType.LEFT);
              targetRoot.fetch(JpaDistributionSet_.type, JoinType.LEFT);
              query.distinct(true);
  
              return predicate;
          };
      }
docs: {@link Specification} for retrieving {@link DistributionSet} with given
  {@link DistributionSet#getId()}.
  
  @param distid
  to search
  @return the {@link DistributionSet} {@link Specification}