Java中ConcurrentHashMap的节点HashEntry 中元素为什么要定义成final的？

Question

static final class HashEntry<K,V> {
    final K key;
    final int hash;
    volatile V value;
    final HashEntry<K,V> next;
}

这样导致在remove节点的时候，需要将remove节点的前面节点全部复制一遍，真的好吗？

Answer 1

When a hash conflict occurs, a linked list will be used to resolve the conflict, but the probability of a hash conflict is very small, and the map will automatically expand to reduce conflicts.

For using final, the Java compiler will ensure that the final field must have been written before reading, that is, ensuring that writing occurs before reading, to avoid writing after reading and reading unexpected values ​​under multi-thread concurrency conditions.

Portal:java memory model final