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 <img width="1920" height="1298" alt="image" src="https://github.com/user-attachments/assets/8c2793b8-70d9-4b39-814d-f16d52100d7a"; /> As shown in the image above, the `DateTimeFormatterBuilder#appendValue` method does not need to call `checkField`; it only needs to be called within `appendInternal`. ------------- PR Comment: https://git.openjdk.org/jdk/pull/28471#issuecomment-3632289875
