code: public static Specification<JpaTargetTag> ofTarget(final String controllerId) {
          return (targetRoot, query, criteriaBuilder) -> {
              final Join<JpaTargetTag, JpaTarget> tagJoin = targetRoot.join(JpaTargetTag_.assignedToTargets);
  
              query.distinct(true);
  
              return criteriaBuilder.equal(tagJoin.get(JpaTarget_.controllerId), controllerId);
          };
  
      }
docs: {@link Specification} for retrieving {@link TargetTag}s by assigned
  {@link Target}.
  
  @param controllerId
  of the target
  
  @return the {@link JpaTargetTag} {@link Specification}