java - 并发ConcurrentHashMap的问题

Question

这个问题的 说明有点长， step1 并发map中的put step2 step3 step4 step5 step6 step7 step8 step9 上面中steop3 表示重复尝试获取锁达到一定的次数之后就 调用lock阻塞当前线程 我想问的问题是关键在 step7 这个...

PHP中文网 · Answer

Thank you for the invitation, but I really can’t answer because first of all I haven’t studied the source code of ConcurrentHashMap myself, and secondly it is almost impossible to ask such details in the interview. Unless you need to write a class library like guava yourself, I don't think it makes much sense to study these.

ringa_lee · Answer

Thank you for the invitation, but I'm sorry, my knowledge of concurrency-related learning is still very limited. Let me help you invite people who may be able to answer it

PHP中文网 · Answer

I’ll answer as many as I can
Question (1) involves the issue of fair locks. If you can’t get it, insert the Node into the queue. Focus on java.util.concurrent.locks.AbstractQueuedSynchronizerjava.util.concurrent.locks.AbstractQueuedSynchronizer 问题（3）线程将自己挂起，这部分的实现是依靠底层的，参照LockSupportProblem (3) The thread hangs itself. The implementation of this part depends on the underlying layer. Please refer to LockSupport

public static void park(Object blocker) {
    Thread t = Thread.currentThread();
    setBlocker(t, blocker);
    unsafe.park(false, 0L);
    setBlocker(t, null);
}

Wake up using unparkmethod