public interface MyService {
  @NotNull String getGreeting(@NotNull String greetee);
}

public class MyServiceImpl implements MyService {
  @NotNull String greeting;

  public void setGreeting(String greeting) {
    this.greeting = greeting;
  }

  public String getGreeting(String greetee) {
    return greeting + " " + greetee;
  }
}

public class TestCase {
  public static void main(String[] args) {
    MyService myService = new MyServiceImpl(); 
    myService.setGreeting("Hello");
    Validator validator = Validation.buildDefaultValidatorFactory().getValidator();
    validator.validate(myService); // throws IllegalArgumentException - wrong number of arguments
  }
}