I have a spring boot service which updates comments for a task. I have to 1) create a comment 2)later award points in another table. So I am adding these in @Transactional method

I am getting error while committing the entity. ConstraintViolation Error. Please see code below

Entities

@Entity
@Table(name = "TASK_COMMENTS")
public class TaskCommentEntity implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @SequenceGenerator(name = "TASK_COMMENTS_TASKCOMMENTSID_GENERATOR", sequenceName = "TASK_COMMENTS_ID_SEQ", allocationSize=1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "TASK_COMMENTS_TASKCOMMENTSID_GENERATOR")
    @Column(name = "TASK_COMMENTS_ID")
    private BigDecimal taskCommentsId;
    
    //other columns

    // bi-directional many-to-one association to TaskEntity
    @ManyToOne
    @JoinColumn(name = "TASK_ID", nullable = false)
    private TaskEntity task;
    
}

@Entity
@Table(name = "TASK")
public class TaskEntity implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @SequenceGenerator(name = "TASK_ID_GENERATOR", sequenceName = "TASK_SEQ", allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "TASK_ID_GENERATOR")
    @Column(name = "TASK_ID")
    private BigDecimal taskId;  
    
    // bi-directional many-to-one association to TaskCommentEntity
    @OneToMany(mappedBy = "task", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    @Fetch(value = FetchMode.SUBSELECT)  // multiple other one-many associations are present. So subselect is used. 
    @OrderBy("updateDt DESC")
    private List<TaskCommentEntity> taskComments = new ArrayList<>();
}   

Controller

@RestController
public class TaskCommentService{

@Autowired//@EJB
TaskCommentBean taskCommentBean;

@PostMapping
public Response saveComment(@RequestBody TaskCommentVO taskCommentVO){
      String userId = getUserId() // gets from session
     taskCommentBean.processComment(taskCommentVO,  userId);
}

}

Bean class

public class TaskCommentBean{

@Autowired
TaskCommentHelper taskCommentHelper;

@Autowired
TaskCommentReviewer taskCommentReviewer;

@PersistanceContext(name = "task.jpa")
EntityManager em;

@Transactional
public void processComment( TaskCommentVO taskCommentVO, String userId)
    TaskEntity taskEntity = em.find(Task.class, taskCommentVO.getTaskId());
    TaskCommentEntity taskCommentEntity = taskCommentHelper.createComment(taskCommentVO, userId); //Isn't returned entity managed by this time ?
    if(taskCommentEntity != null){
     
         Boolean clean =   taskCommentReviewer.reviewComment(taskCommentVO.getCommentText());
          if(clean){
             taskCommentEntity.setCleanStatus("Y") 
         }

       taskCommentEntity.setTask(taskEntity);  // setting foreign key Many-to-one variable of managed entity. 
                                              //  This is NOT getting set.
       taskEntity.addTaskComment(taskCommentEntity);
         
       em.merge(  taskCommentEntity);  // did not help
       em.merge(  taskEntity);   //did not help


       // Update other tables 
        em.persist()
       // some times , here I get Connection closed Error. This is another issue.
    }
}

TaskCommentHelper

Public class TaskCommentHelper{
  @PersistanceContext(name = "task.jpa")
    EntityManager em;

   public TaskCommentEntity createComment(TaskCommentVO taskCommentVO){
            TaskCommentEntity entity = new TaskCommentEntity();
            entity.setCommentText(taskcommentVO.getCommentText());
            // sets few more fields
            
      em.persist();
      return entity;
     } 
}

On completion of transactional method, I am getting constraint violation error. java.sql.SQLIntegrityConstraintViolationException: ORA-01400: cannot insert NULL into ("TASK_COMMENTS"."TASK_ID") Isn't updating managed entity a valid step. Can't I set it foreign key variable.

This works fine if I pass and set the taskEntity inside the TaskCommentHelper.createComment() method before em.persist();

public TaskCommentEntity createComment(TaskCommentVO taskCommentVO, TaskEntity taskEntity){
                TaskCommentEntity entity = new TaskCommentEntity();
                entity.setCommentText(taskcommentVO.getCommentText());
                // sets few more fields
          entity.setTask( taskEntity);   // With this change - Works fine.
          em.persist(entity);
          return entity;
         }

Also with this approach, other variable setCleanStatus(Y) is commited even when it is set after em.persist() in the caller method taskCommentBean.processComment();

Please let me know what needs to be corrected. Is it related to SpringBoot Transaction boundaries or something else.