Customizing REST API Error Response in Spring Boot / Spring-Security-OAuth2
Defining error format is important part of REST API design.
Spring-Boot and Spring Security provide pretty nice error handling for RESTful APIs out of the box. Although it has to be documented, especially when contract-first approach to API design is used.
It is good idea to follow some common format for error responses. But OAuth2 specification and Spring Boot format may not satisfy those requirements.