Suppose I like the default error handling of Spring Boot for Spring Web MVC, but I just want to return a different HTTP status for specific exceptions: for instance, I would like to return 404 when a FileNotFoundException is thrown, instead of the default 500.

The quickest way to do this would be to define a @Bean implementing ErrorAttributes, by extending DefaultErrorAttributes changing just addStatus(Map<String, Object>, RequestAttributes) to return 404 in case getError(WebRequest) returns a FileNotFoundException. However, this is not currently possible because addStatus(Map<String, Object>, RequestAttributes) is private!

Other methods like addErrorDetails(Map<String, Object>, WebRequest, boolean), addErrorMessage(Map<String, Object>, Throwable) and addStackTrace(Map<String, Object>, Throwable) could simplify quick customisations if they were protected...