Why JPA update entity causes stackoverflow？ - jpa

Question

I have an entity Task with id. Tasks belongs to Config. I need to update Task with it's Config doesn't change. Here is my code:
Task:
#Entity
#Getter
#Setter
public class Task{
#ManyToOne
#JoinColumn(name = "config_id", referencedColumnName = "id")
private Config config;
#OneToMany(orphanRemoval = true,cascade = CascadeType.ALL)
#JoinColumn(name="task_id")
private Set<ActivityItemTask> activityItemTasks = new HashSet<>();
}
#Entity
public class ActivityItemTask {
private Double score;
#EmbeddedId
private ActivityItemTaskId activityItemTaskId;
#Getter
#Setter
#Embeddable
#NoArgsConstructor
#AllArgsConstructor
public static class ActivityItemTaskId implements Serializable {
#ManyToOne
#JoinColumn(name = "activity_item_id")
private ActivityItem activityItem;
#ManyToOne
#JoinColumn(name = "task_id")
private Task task;
#ManyToOne
#JoinColumn(name = "config_id")
private TaskConfig config;
}
}
Config:
#Entity
#Getter
#Setter
public class Config{
#OneToMany(mappedBy = "config")
private Set<Task> tasks = new HashSet<>();
}
TaskService:
#Service
public class TaskService{
#Resource
TaskRepository taskRepository;
#Transactional
public Long save(Taskdto dto){
Config config = new Config();
config.setId(task.getConfigId());
s.setTaskConfig(config);
return taskRepository.save(s).getId();
}
}
TaskDto:
#Data
public class TaskDto {
private Long id;
#NotNull
private Long configId;
private String name;
private Date beginDate;
private Date endDate;
private String note;
}
when TaskService#save was called , it throw StackOverflowException:
org.springframework.web.util.NestedServletException: Handler dispatch failed; nested exception is java.lang.StackOverflowError
the log shows that my application querys task record and querys task's config and config's tasks and so on.
I am wondering what's wrong with my association annation. Any advice are appreciated.
I'm sorry.I have written another 2 calss so that I can find out the truth. It turns out my third calss ActivityItemTask may be the root cause. I think Task. activityItemTasks may should be annnotation with mappedBy=? But which field should be writtern here?

Answer 1

I did config wrong association.
Task should be :
#OneToMany(mappedBy = "activityItemTaskId.task")
// #JoinColumn(name = "task_id")
private Set<ActivityItemTask> activityItemTasks = new HashSet<>();
This is how to use mappedBy annotation with embedable class.
Thank all you guys commented or answered. You did help me find it out.