锁

刺骨的言语ヽ痛彻心扉 2022-01-28 07:09 55阅读 0赞

synchronized关键字：  
类锁，对象锁，同步代码块  
[https://blog.csdn.net/cs408/article/details/48930803\#commentBox][https_blog.csdn.net_cs408_article_details_48930803_commentBox]  
synchronized monitorEneter，可重入；对象头  
[https://blog.csdn.net/u011277123/article/details/85061655][https_blog.csdn.net_u011277123_article_details_85061655]  
[https://juejin.im/post/5ae6dc04f265da0ba351d3ff\#heading-4][https_juejin.im_post_5ae6dc04f265da0ba351d3ff_heading-4]  
搞懂并发编程，轻松应对80%的面试场景  
[https://www.toutiao.com/i6631353575584825870/?group\_id=6631353575584825870][https_www.toutiao.com_i6631353575584825870_group_id_6631353575584825870]

死锁

解决死锁的手段

保证多个线程按照相同的顺序获取锁  
设置获取锁的超时时间，超过设定时间以后自动释放  
死锁检测  
资源限制

「阿里面试系列」Java线程的应用及挑战  
原子性，有序性，可见性 [https://www.jianshu.com/p/cf57726e77f2][https_www.jianshu.com_p_cf57726e77f2]  
面试官最爱的volatile关键字：[https://juejin.im/post/5a2b53b7f265da432a7b821c][https_juejin.im_post_5a2b53b7f265da432a7b821c]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2E0NDY3MTIzODU_size_16_color_FFFFFF_t_70]  
主要是禁止重排序，初始化一个实例（SomeType st = new SomeType()）在java字节码中会有4个步骤，申请内存空间，初始化默认值（区别于构造器方法的初始化），执行构造器方法连接引用和实例。这4个步骤后两个有可能会重排序，1234 1243都有可能，造成未初始化完全的对象发布。volatile可以禁止指令重排序，从而避免这个问题

作者：陈鹏  
链接：[https://www.zhihu.com/question/56606703/answer/149894860][https_www.zhihu.com_question_56606703_answer_149894860]  
Java 并发：Lock 框架详解

[https://blog.csdn.net/justloveyou\_/article/details/54972105\#commentBox][https_blog.csdn.net_justloveyou_article_details_54972105_commentBox]

不可不说的Java“锁”事  
[https://tech.meituan.com/2018/11/15/java-lock.html][https_tech.meituan.com_2018_11_15_java-lock.html]

vector：

Vector和ArrayList的最大不同是Vector是线程安全的而ArrayList不是。
    Vector几乎所有的方法都使用synchronized关键字是来保证线程安全使它的性能比不上ArrayList。

Vector和ArrayList不同还体现在动态增长的策略上。ArrayList的基本增长策略是oldCapacity*1.5+1，如果还不够则容量为实际需要容量；Vector的基本增长策略是oldCapacity+设定好的增长幅度，如果没设定则新容量增长为oldCapacity*2，如果还不够则为实际需要的容量。  
　　collections：  
[https://blog.csdn.net/u011240877/article/details/52773577\#commentBox][https_blog.csdn.net_u011240877_article_details_52773577_commentBox]  
ConcurrentHashMap源码分析（JDK8版本）  
[https://blog.csdn.net/u010723709/article/details/48007881\#commentBox][https_blog.csdn.net_u010723709_article_details_48007881_commentBox]

hashmap源码分析：  
Java 集合深入理解（16）：HashMap 主要特点和关键方法源码解读  
[https://blog.csdn.net/u011240877/article/details/53351188\#commentBox][https_blog.csdn.net_u011240877_article_details_53351188_commentBox]  
hashmap线程不安全：  
[https://www.jianshu.com/p/e2f75c8cce01][https_www.jianshu.com_p_e2f75c8cce01]

[https_blog.csdn.net_cs408_article_details_48930803_commentBox]: https://blog.csdn.net/cs408/article/details/48930803#commentBox
[https_blog.csdn.net_u011277123_article_details_85061655]: https://blog.csdn.net/u011277123/article/details/85061655
[https_juejin.im_post_5ae6dc04f265da0ba351d3ff_heading-4]: https://juejin.im/post/5ae6dc04f265da0ba351d3ff#heading-4
[https_www.toutiao.com_i6631353575584825870_group_id_6631353575584825870]: https://www.toutiao.com/i6631353575584825870/?group_id=6631353575584825870
[https_www.jianshu.com_p_cf57726e77f2]: https://www.jianshu.com/p/cf57726e77f2
[https_juejin.im_post_5a2b53b7f265da432a7b821c]: https://juejin.im/post/5a2b53b7f265da432a7b821c
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2E0NDY3MTIzODU_size_16_color_FFFFFF_t_70]: /images/20220128/fb9697abc7284245b888453272a21347.png
[https_www.zhihu.com_question_56606703_answer_149894860]: https://www.zhihu.com/question/56606703/answer/149894860
[https_blog.csdn.net_justloveyou_article_details_54972105_commentBox]: https://blog.csdn.net/justloveyou_/article/details/54972105#commentBox
[https_tech.meituan.com_2018_11_15_java-lock.html]: https://tech.meituan.com/2018/11/15/java-lock.html
[https_blog.csdn.net_u011240877_article_details_52773577_commentBox]: https://blog.csdn.net/u011240877/article/details/52773577#commentBox
[https_blog.csdn.net_u010723709_article_details_48007881_commentBox]: https://blog.csdn.net/u010723709/article/details/48007881#commentBox
[https_blog.csdn.net_u011240877_article_details_53351188_commentBox]: https://blog.csdn.net/u011240877/article/details/53351188#commentBox
[https_www.jianshu.com_p_e2f75c8cce01]: https://www.jianshu.com/p/e2f75c8cce01