Solve the problem of @onetomany query falling into circular reference

solve @OneToMany Query caught in circular reference problem

The error report of the problem is as follows ：

The main information is ：wrapping Result set representing update count of 4>
as well as ：exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause

The original configuration ：

The reason for the error is that both classes use the method of urgent loading , It will cause the entity class that has been looking for foreign keys to fall into a loop , To report a mistake .

Solution ： Change to as needed LAZY that will do
@OneToMany( fetch = FetchType.LAZY)

success result:

Reference material ：https://www.v2ex.com/t/541510
I've tried to annotate it , But it didn't solve my problem , It turned out to be fetch The problem of .