Помогите разгрести кашу в голове. Валидатор указывает на проблему в следующих классах: 
public class CurrencyManipulatorFactory {
    private static Map<String, CurrencyManipulator> map = new HashMap<>();

    private CurrencyManipulatorFactory(){

    }

    public static CurrencyManipulator getManipulatorByCurrencyCode(String currencyCode){
        return new CurrencyManipulator(currencyCode);
    }
//Проблема туть:
    public static Collection<CurrencyManipulator> getAllCurrencyManipulators(){
        return new ArrayList<>(map.values());
    }
}
class InfoCommand implements Command {
    @Override
    public void execute() {
        Collection<CurrencyManipulator> currencyManipulators = CurrencyManipulatorFactory.getAllCurrencyManipulators();
        if (currencyManipulators.isEmpty()) {
            ConsoleHelper.writeMessage("No money available.");
        }
        for (CurrencyManipulator currencyManipulator : currencyManipulators) {
            if (currencyManipulator.hasMoney()) {
                ConsoleHelper.writeMessage(currencyManipulator.getCurrencyCode().toUpperCase() + " - " + currencyManipulator.getTotalAmount());
            } else {
                ConsoleHelper.writeMessage("No money available.");
            }
        }
    }