@Component
public class LittleServiceFactory {
    @Autowired
    private LegacyLittleService legacy;

    @Autowired
    private NewShinyLittleService newShiny;

    @Autowired
    private TheSessionScopedBean theSessionScopedBean;

    public LittleService get() {
        if (theSessionScopedBean.shouldUseLegacy()) {
            return legacy;
        }
        else {
            return newShiny;
        }
    }
}