@Service
public class EmailService {

    private Context context;
    //.. тут обитают драконы

    //использование контекста
   public void sendRegistrationEmail() {
     String registrationEmailBody = getRegConfirmMessage(context);
     MimeMessage registrationMessage = createMimeMessage(registrationEmailBody, recepientName);
     sendCommonEmail(registrationMessage);

    }
 }


@Controller
public class DevController {

    private EmailService emailService;

    public DevController(EmailService emailService) {
        this.emailService = emailService;
    }

    @ResponseBody
    @GetMapping("/someWay/subway/send/registration")
    public String sendEmail(){
        Context ctx = new Context();
        ctx.setVariable("confirmationLink", "google.com");
        emailService.setContext(ctx);
        emailService.setRecepientName("userName@gmail.com");
        emailService.sendRegistrationEmail();
        return "OK!";
    }