package basic;

/**

* @Author: ChangXuan

* @Decription: 单例模式

* 双重校验锁

* @Date: 15:07 2020/11/15

**/

public class Singleton {

// 使用 volatile 禁止JVM指令重排序

private volatile static Singleton uniqueInstance;

private Singleton(){}

public static Singleton getUniqueInstance() {

if (uniqueInstance == null) {

synchronized (Singleton.class) {

if (uniqueInstance == null) {

uniqueInstance = new Singleton();

}

}

}

return uniqueInstance;

}

}