On Tue, 30 Sep 2025 03:25:28 GMT, Shaojin Wen <[email protected]> wrote:
>> The DateTimeFormatterBuilder::FIELD_MAP is of type Map<Character, >> TemporalField>, with key values in the range 'A-Z' and 'a-z'. >> >> We can change the type of FIELD_MAP to an array of length 128 and then use >> char as an index to access the array. >> >> This will reduce the memory usage of DateTimeFormatterBuilder::FIELD_MAP and >> improve performance slightly. >> >> By analyzing the jmap dump memory, we can see that the memory size used by >> DateTimeFormatterBuilder::FIELD_MAP has dropped from 1.12kb to 528b, the >> number of objects has decreased and the memory has become more flat. as >> shown below: >> * before >> <img width="2018" height="1016" alt="image" >> src="https://github.com/user-attachments/assets/57d4c513-55c7-472e-95a8-9f7a4b47662d"; >> /> >> >> * after >> <img width="1894" height="352" alt="image" >> src="https://github.com/user-attachments/assets/89cbfb6c-360a-475f-85ea-4365d3b66871"; >> /> > > Shaojin Wen has updated the pull request incrementally with one additional > commit since the last revision: > > use switch, from @RogerRiggs & @cl4es src/java.base/share/classes/java/time/format/DateTimeFormatterBuilder.java line 126: > 124: import jdk.internal.util.DateTimeHelper; > 125: import jdk.internal.util.DecimalDigits; > 126: import jdk.internal.vm.annotation.Stable; Leftover? src/java.base/share/classes/java/time/format/DateTimeFormatterBuilder.java line 2227: > 2225: // LDML - U - cycle year name, not supported by 310 yet > 2226: // LDML - l - deprecated > 2227: // LDML - j - not relevant Do not remove these informational comments ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/26634#discussion_r2392196321 PR Review Comment: https://git.openjdk.org/jdk/pull/26634#discussion_r2392210599
