JMM与DCL失效探究  

Study on JMM and DCL Invalidation

作　　者：徐茜亮[1] 王成良[1] 王远斌[1] 

机构地区：[1]重庆大学计算机学院,重庆400044

出　　处：《微处理机》2005年第6期53-56,共4页Microprocessors

摘　　要：Java提供的synchronized关键字可使多线程实现同步,但也会导致双重检查锁定(Double-Checked Locking,DCL)失效。一般采用继承ThreadLocal类的方式来避免这种失效,但实现效率低,性能损失大。针对这些不足,本文结合实例分析了Java内存模型(JMM)、DCL失效原因以及ThreadLocal的内部运行机制,给出了将类的对象设计成Singleton模式的策略。The keyword “synchronized” provide by Java can make multithreading realize synchronization , but it can also make Double -Checked locking（DCL） become invalid. The invalidation can be avoided by inheriting “Threadlocal” class. But, the efficiently becomes lower and the performance loses greater. Based on the deficiency, this paper analyses Java Memory Model （jMM） , the reason for DCL invalidation and the interior mechanism of “Threadlocal”. The strategy to design the object of class by singleton model is proposed.

关 键 词：Java内存模型 双重检查锁定 ThreadLocal方式 SINGLETON模式 

分 类 号：TP3[自动化与计算机技术—计算机科学与技术]