itwanger / itwanger/toBeBetterJavaer
如果键的哈希值已经在数组中存在，调用equals判断是否相同，相同则覆盖。
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Description
[能说一下 HashMap 的底层数据结构吗？
不过，链表过长时，查询效率会比较低，于是当链表的长度超过 8 时（且数组的长度大于 64），链表就会转换为红黑树。红黑树的查询效率是 O(logn)，比链表的 O(n) 要快。
hash() 方法的目标是尽量减少哈希冲突，保证元素能够均匀地分布在数组的每个位置上。
static final int hash(Object key) {
int h;
return (key == null) ? 0 : (h = key.hashCode()) ^ (h >>> 16);
}
如果键的哈希值已经在数组中存在，其对应的值将被新值覆盖。
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First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Locate the HashMap explanation containing the hash() method and the statement about replacing values. Clarify the documented behavior around hash collisions and equality, then verify that the surrounding explanation remains accurate and understandable.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- java
- Domain
- documentation
- Issue type
- Documentation
- Difficulty
- 2/5
- Estimated time
- 1-3 hours
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 35/100