Once #28187 provides ProblemDetail along with the ErrorResponse hierarchy of exceptions that encapsulate HTTP status, headers, and body, to support RFC 7807, it is also necessary to improve content negotiation and formatting specifically for error responses.

In Spring MVC it is possible to configure content type resolution and message conversion and likewise in WebFlux to configure content type resolution and message codecs, but those apply to both @RequestMapping and @ExceptionHandler methods.

Error handling however has a different perspective. The range of supported media types might be more limited and different, e.g. only application/problem+json. The resolution of the request content type might also be done differently, .e.g. defaulting to application/problem+json if not explicitly requested, or perhaps even enforcing it.

Such a mechanism is also a convenient place for other configuration related to how ProblemDetail should be rendered..