双重锁定的单例种

双重锁定的单例类

public class Singleton {private static Singleton instance;private static  Object syncRoot = new Object();private Singleton() {}public static Singleton getInstance(){if(instance == null){synchronized (syncRoot) {if(instance == null){instance = new Singleton();}}}return instance;}

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线程安全下的单例类 ，双重锁定哦 ?

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