Spring Boot Tutorial 0/110 lessons ~6 min read Lesson 21“Production-grade backends”

Exception Handling

Centralised exception handling turns scattered try/catch into a single, consistent error contract.

Course progress0%

Focus

3 guided sections

Practice signal

Examples included

Career prep

Foundation builder

Introduction

Centralised exception handling turns scattered try/catch into a single, consistent error contract. Pair @ControllerAdvice with custom domain exceptions and you'll never write a try/catch in a controller again.

Informative example

// Domain exception
public class NotFoundException extends RuntimeException {
  public NotFoundException(String msg) { super(msg); }
}

// Global handler
@RestControllerAdvice
public class ApiExceptionHandler {

  record ApiError(String code, String message, Instant timestamp) {}

  @ExceptionHandler(NotFoundException.class)
  public ResponseEntity<ApiError> notFound(NotFoundException ex) {
    return ResponseEntity.status(404)
        .body(new ApiError("not_found", ex.getMessage(), Instant.now()));
  }

  @ExceptionHandler(MethodArgumentNotValidException.class)
  public ResponseEntity<ApiError> validation(MethodArgumentNotValidException ex) {
    String msg = ex.getBindingResult().getFieldErrors().stream()
        .map(e -> e.getField() + ": " + e.getDefaultMessage())
        .collect(Collectors.joining("; "));
    return ResponseEntity.badRequest()
        .body(new ApiError("validation_error", msg, Instant.now()));
  }

  @ExceptionHandler(Exception.class)
  public ResponseEntity<ApiError> fallback(Exception ex) {
    log.error("Unhandled", ex);
    return ResponseEntity.status(500)
        .body(new ApiError("internal_error", "Something went wrong", Instant.now()));
  }
}

Best practices

Define a single error envelope shape for the whole API (RFC 7807 Problem JSON is great).
Map domain exceptions to HTTP status; never leak stack traces to clients.
Log full context server-side with a trace ID, return a short user message.

Ready to mark this lesson complete?Track your journey across the entire course.