Singleton, leveraging to classloader

MustBeSingleton.java

public class MustBeSingleton {

    private MustBeSingleton() {
    }

    public static MustBeSingleton getInstance() {
        return SINGLETON_LOADER.singleton;
    }

    private static class SINGLETON_LOADER {
        static final MustBeSingleton singleton = new MustBeSingleton();
    }
}