question: @ ExceptionHandler ( ConstraintViolationException . class ) @ ResponseStatus ( value = HttpStatus . BAD_REQUEST ) public Map < String , Object > handleConstraintViolationException ( ConstraintViolationException ex ) { Collection < FieldError > errors = FieldError . getErrors ( ex . getConstraintViolations ( ) ) ; log . warn ( "ConstraintViolationException: " + errors . toString ( ) ) ; return LemonUtil . mapOf ( "exception" , "ConstraintViolationException" , "errors" , errors ) ; }
target:  Handles constraint violation exceptions