عرض عملي: معالجة مركزية للأخطاء باستخدام Problem Details

خطوة بخطوة

1. Add the exception hierarchy and make ProductService throw NotFoundException.
2. Create ApiExceptionHandler with handlers for not found and conflict.
3. Add a handler for MethodArgumentNotValidException that returns field errors in a property.
4. Planned mistake: a catch-all that returns ex.getMessage() leaks a database message. Fix: log it, return a generic detail.
5. Call each case with curl and compare the bodies.