On Mon, 9 Jan 2023 17:09:02 GMT, Sergey Bylokhov <s...@openjdk.org> wrote:
>> Viktor Klang has updated the pull request incrementally with two additional >> commits since the last revision: >> >> - 8299444: java.util.Set.copyOf allocates needlessly for empty input >> collections >> >> Modifies ImmutableCollections.listCopy: >> Introduces a check for isEmpty to avoid allocation in the case of an >> empty input collection. >> - 8299444: java.util.Set.copyOf allocates needlessly for empty input >> collections >> >> Modifies Map.copyOf: >> Introduces a check for isEmpty to avoid allocation in the case of an >> empty input Map. > > I wonder how it will affect (if any) the performance of the common path, for > example if non-empty but small ConcurrentHashMap is passed to the > List.copyOf(). @mrserb The "hit" is directly proportional to the cost of `isEmpty()`—but specifically for collections like ConcurrentHashMap, the very notion of "current size" is challenging at best. ------------- PR: https://git.openjdk.org/jdk/pull/11847
