I want to return status code of 400 instead of 500 about unhandled exceptions, globally - spring

Question

I am trying to make 500 Internal Server Error to 400 Bad Request in every cases.
This is my package structure for exceptions.
For example, ConflictExeption looks like this.
#ResponseStatus(HttpStatus.CONFLICT)
public class ConflictException extends ApiException {
public ConflictException(String message) {
super(message);
}
public ConflictException() {
this("Conflict Exception.");
}
}
public class ApiException extends RuntimeException {
public ApiException(String message) {
super(message);
}
}
public class UserEmailInUseException extends ConflictException{
public static final String MESSAGE = "Desired email is already in use.";
public UserEmailInUseException() {
super(MESSAGE);
}
}
Below is my simple service code.
#Service
public class UsersService {
#Transactional
public UserInfoResponseDto signUp(UserSignupRequestDto requestDto) {
if (usersRepository.findByEmail(requestDto.getEmail()).isPresent()) throw new
UserEmailInUseException();
return new UserInfoResponseDto(usersRepository.save(requestDto.toEntity()));
}
}
UserEmailInUseException extends ConflictException.
In my case, 500 error occurs when some violations are made while making transaction with MariaDB.
Simply put, I just want to return status code of 400 instead of 500, where exception is not handled.
Thanks in advance!
Also, I've tried this example below, and it seems to send 500..
Link

Answer 1

Have you tried:
#RestControllerAdvice
public class RestErrorHandler {
#ExceptionHandler
#ResponseStatus(BAD_REQUEST)
Exception handleUnhandledException(Exception e) {
return e;
}
}

Answer 2

First of all you are mapping it to CONFLICT instead of BAD_REQUEST. Have you tried the following annotation setting?
#ResponseStatus(HttpStatus.BAD_REQUEST)
If you don't want to change existing ConflictException try to introduce a new base exception as follows:
#ResponseStatus(HttpStatus.BAD_REQUEST)
public class BadRequestException extends ApiException {
// [...]
}