java 设计模式，单例设计模式

class test{public static void main(String[] args) {Single s = Single.getInstance();System.out.println(s);Single2 s2 = Single2.getInstance();System.out.println(s2);}}/*饿汉模式*/class Single{public static Single s =  new Single();private Single(){}public static Single getInstance() {return s;}}/* 懒汉模式*/class Single2{public static Single2 s = null;private Single2(){};public static Single2 getInstance() {if (s == null) {s = new Single2();}return s;}}