Find the problem in this service usage:

Find the problem in this service usage:

@Injectable({ providedIn: 'root' })
export class LoggerService { log(msg: string) { console.log(msg); } }
@Component({ selector: 'app-log', template: '' })
export class LogComponent {
  constructor() {
    this.logger.log('Test');
  }
  private logger: LoggerService;
}