Double Check LOCK（DCL）实现单例

public class Singleton{
        private static Singleton sInstance = null;
        private Singleton(){
        }
        public static Singleton getInstance(){
                if(sInstance == null){
                        synchronized(Singleton.class){
                                if(sInstance == null){
                                        sInstance = new Singleton();
                                }
                        }
                }
                return sInstance;
        }
}

Double Check LOCK（DCL）实现单例

原文：https://blog.51cto.com/williamnw/2540402