JAVA 多线程-单例设计模式-懒汉式

//仅作为学习笔记

/*单例设计模式/*饿汉式//饿汉式在多线程中 比懒汉式更安全高效 不会出现一个对象被实例化多次class Single{private static final Single s = new Single();private Single(){}public static Single getInstance(){return s;}}*/*///懒汉式//延迟加载class Single{private static Single s = null;private Single(){}public static Single getInstance(){if(s==null){synchronized(Single.class)//以本类对象的字节码为锁{if(s== null)s=new Single();}}return s;}}class SingleDemo{public static void main(String []args){System.out.println("Hello world");}}