Initialization-on-demand holder idiom 单例

在​​wikipedia​​中看到一种单例，效果不错，分享一下。

public class Something {
    private Something() {}

    private static class LazyHolder {
        static final Something INSTANCE = new Something();
    }

    public static Something getInstance() {
        return LazyHolder.INSTANCE;
    }
}

参考：

​​http://ifeve.com/initialization-on-demand-holder-idiom/​​