On Thu, 18 Jan 2024 07:17:20 GMT, ExE Boss <d...@openjdk.org> wrote:
>> src/java.base/share/classes/java/util/concurrent/ConcurrentHashMap.java line
>> 1088:
>>
>>> 1086: public void putAll(Map<? extends K, ? extends V> m) {
>>> 1087: if (table != null) {
>>> 1088: tryPresize(size() + m.size());
>>
>> Is overflow not an issue here because calling tryPresize with a negative
>> value will invoke tableSizeFor?
>
> When `tableSizeFor` is called with a negative value greater than
> `Integer.MIN_VALUE`, it’ll just return `+1`:
> https://github.com/openjdk/jdk/blob/ff8cc268fdaaf85299c94088a226b73e7eaf6bdb/src/java.base/share/classes/java/util/concurrent/ConcurrentHashMap.java#L704-L707
>
> This will in turn cause `tryPresize` to do nothing when `table` is already
> initialized.
In the worse case with overflow, we may not presize when we would have liked.
I'd like to say its an edge case we don't have to cover. The sum of map sizes
would have to be 2^31. Not sure if maps ever get this big in practice.
If its a concern, we could do `max(this.size() + m.size(), m.size())`. I feel
its unnecessary.
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PR Review Comment: https://git.openjdk.org/jdk/pull/17116#discussion_r1459529675
