I have 3 entities : EntityEntity, EntityTaskEntity and EntityTaskStatusEntity.
EntityEntity has the following properties:

@Entity
@Table(name = "entities")
@Getter @Setter
@AllArgsConstructor @NoArgsConstructor
@EqualsAndHashCode
public class EntityEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(length = 30)
    private String entityId;

    @Column(length = 100, unique = true)
    private String name;

    @OneToMany(mappedBy = "entity", cascade={CascadeType.ALL}, fetch = FetchType.EAGER)
    private List<EntityTaskEntity> entityTasks;
}

EntiTaskEntity has the following implementation:

@Entity
@Table(name = "entity_tasks")
public class EntityTaskEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(length = 30, unique = true)
    private String entityTaskId;

    @Column(length = 100)
    private String workflowTaskName;
    
    @ManyToOne(cascade={CascadeType.PERSIST, CascadeType.MERGE}, fetch = FetchType.EAGER)
    @JoinColumn(name = "entity_task_status_id")
    private EntityTaskStatusEntity status;

    @JsonBackReference
    @ManyToOne(fetch = FetchType.LAZY)
    private EntityEntity parentEntity;

    @JsonManagedReference
    @OneToMany(mappedBy = "parentEntity")
    private List<EntityEntity> childEntities;
}

Finally, the EntityTaskStatusEntity:

@Entity
@Table(name = "entity_task_statuses")
@Getter @Setter
@AllArgsConstructor @NoArgsConstructor
@EqualsAndHashCode
public class EntityTaskStatusEntity {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(length = 30, unique = true)
    private String entityTaskStatusId;

    @Column(length = 100, unique = true)
    private String name;
}

I do use jpa repositories and do queries on EntityEntity using entityId which is unique.
I do queries on EntityTaskStatusEntity using entityTaskStatusId which is also unique.

I have the following method in java for creating a Specification:

private Specification<EntityEntity> entitySpecificationQueryConfigurer (
        List<String> entityTaskStatusIdParams, ...) {
    return (root, query, criteriaBuilder) -> {
        List<Predicate> predicates = new ArrayList<>();
        if(entityTaskStatusIdParams != null) {
            predicates.add(setInPredicate(
                    entityTaskStatusIdParams, root, query, criteriaBuilder));
            root.fetch("childEntities", JoinType.LEFT);
        }
        // I have other predicates....
        return criteriaBuilder.and(predicates.toArray(new Predicate[0]));

    };
}

My call to this entitySpecificationQueryConfigurer

Specification<EntityEntity> specification = entitySpecificationQueryConfigurer(entityTaskStatusIdParams);
List<EntityEntity> entityEntities = repository.findAll(specification);

Here is my implementation of setInPredicate:

private Predicate setAllInPredicate(
        String paramString,
        Root<EntityEntity> root,
        CriteriaQuery<?> query,
        CriteriaBuilder criteriaBuilder) {
    Set<String> entityTaskStatusIdParams = Stream.of(paramString.split(","))
            .collect(Collectors.toSet());
    // Subquery to count all tasks of an entity
    Subquery<Long> totalTasksSubquery = query.subquery(Long.class);
    Root<EntityTaskEntity> taskRoot = totalTasksSubquery.from(EntityTaskEntity.class);
    totalTasksSubquery.select(criteriaBuilder.count(taskRoot.get("id")));
    totalTasksSubquery.where(criteriaBuilder.equal(taskRoot.get("entity"), root));

    // Subquery to count tasks of an entity with statuses in the given list
    Subquery<Long> matchedTasksSubquery = query.subquery(Long.class);
    Root<EntityTaskEntity> matchedTaskRoot = matchedTasksSubquery.from(EntityTaskEntity.class);
    matchedTasksSubquery.select(criteriaBuilder.count(matchedTaskRoot.get("id")));
    Join<EntityTaskEntity, EntityTaskStatusEntity> statusJoin = matchedTaskRoot.join("status");
    matchedTasksSubquery.where(criteriaBuilder.and(
            criteriaBuilder.equal(matchedTaskRoot.get("entity"), root),
            statusJoin.get("entityTaskStatusId").in(entityTaskStatusIdParams)
    ));

    // Ensure the total number of tasks is equal to the number of matched tasks
    return criteriaBuilder.equal(totalTasksSubquery, matchedTasksSubquery);
}

In my entitySpecificationQueryConfigurer method I do have several predicates I use for my Specification.

My issue is that i don’t retrieve childEntities in my results. If i don’t have any entityTaskStatusIdParams then my results return childEntities…