https://www.google.com.hk/search?q=%E5%81%8F%E5%90%91%E9%94%81%E3%80%81%E8%BD%BB%E9%87%8F%E7%BA%A7%E9%94%81%E5%92%8C%E9%87%8D%E9%87%8F%E7%BA%A7%E9%94%81&oq=pian%27xiang%27suo&aqs=chrome.2.69i57j0l2.6428j0j7&sourceid=chrome&ie=UTF-8
Java并发编程：Synchronized底层优化（偏向锁、轻量级锁）
原文：https://www.cnblogs.com/gotodsp/p/8831035.html