package singleton;

public class AppConfigNaiveLazy {

    private static AppConfigNaiveLazy instance; // null until first request

    private AppConfigNaiveLazy() { /* load config */ }

    // BROKEN IN MULTITHREADED CODE — see explanation below
    public static AppConfigNaiveLazy getInstance() {
        if (instance == null) {                    // Thread A: checks, sees null
            instance = new AppConfigNaiveLazy();    // Thread B: also sees null, also enters here
        }                                           // Both threads create a new AppConfigNaiveLazy!
        return instance;
    }
}