package Ġpl . pol sl . timetable . user Ċ Ċ import Ġorg . springframework . http . HttpStatus Ċ import Ġorg . springframework . web . bind . annotation . ResponseStatus Ċ Ċ @ ResponseStatus ( value Ġ= ĠHttpStatus . BAD _ REQUEST ) Ċ class ĠInvalid Username Exception ( message : ĠString ): ĠRuntimeException ( message )