class Singleton{        private static Singleton instance;//类Feild：instance           private Singleton()//构造器         {}        public static Singleton getInstance()//特殊方法，可以访问构造器        {                if (instance == null)                {                        intance = new Singleton();                }                return instance;        }}public class SingleTest{        public static void main(String[] args)        {                Singleton s1 = Singleton.getInstance();                Singleton s2 = Singleton.getInstance();                System.out.println(s1==s2);        }}