On Tue, 9 Dec 2025 10:02:36 GMT, Shaojin Wen <[email protected]> wrote:
>> This PR optimizes the parsing performance of DateTimeFormatter by replacing >> HashMap with EnumMap in scenarios where the keys are exclusively ChronoField >> enum values. >> >> When parsing date/time strings, DateTimeFormatter creates HashMaps to store >> intermediate parsed values. HashMap has more overhead for operations >> compared to specialized map implementations. >> >> Since ChronoField is an enum and all keys in these maps are ChronoField >> instances, we can use EnumMap instead, which provides better performance for >> enum keys due to its optimized internal structure. >> >> Parsing scenarios show improvements from 12% to 95% > > Shaojin Wen has updated the pull request incrementally with one additional > commit since the last revision: > > remove redundant checkField This PR has been through too many incremental changes. I suspect a better solution is to implement a fit-for-purpose Map, optimized for ChronoFields but taking into account the possibility of unknown TemporalFields. All within the implementation of a Map<TemporalField, Long>. I'd like to see this PR closed and take a fresh look with all that is learned by the attempt. ------------- Changes requested by rriggs (Reviewer). PR Review: https://git.openjdk.org/jdk/pull/28471#pullrequestreview-3601320108
