Steps to reproduce:
- create two entities with a JPA-one-to-many-relationship between the two
- annotate both classes with lombok's @Data (generating e.g. toString())
- set logging.level.org.springframework.web to DEBUG
- POST a new child object with a parent reference
- Spot the exception. In my case, backend state was correct, frontend stopped working.
Lombok's autogenerated toString() methods probably result in an endless loop in this call:
Besides excluding some fields from being toStringified() by lombok, this method probably shouldn't throw an error in any case so you might consider try-catching the call.