8334742: Change java.time month/day field types to 'byte'

[gauthamkrishnanibm]

In the following classes, month and day values are stored in fields of type 'int' or 'short'. The range of allowed values is small enough that the type can be 'byte' instead.

java.time.YearMonth
java.time.MonthDay
java.time.LocalDate
java.time.chono.HijrahDate

Refactoring the type will give the JVM a little more layout flexibility, and will be especially useful when these classes become value classes.

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Issue

• JDK-8334742: Change java.time month/day field types to 'byte' (Bug - P4)

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[openjdk]

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[mlbridge]

Webrevs

• 01: Full - Incremental (148c3834)
• 00: Full (e198afb2)

[naotoj]

Since they are serialized fields (except Hijrah ones), I don't think this is doable.

[gauthamkrishnanibm]

@naotoj Thanks for reviewing.

You are right.
But when I checked these classes use a custom Externalizable encoding (see 'readExternal'/'writeExternal'), which already stores these values as bytes.

[naotoj]

But when I checked these classes use a custom Externalizable encoding (see 'readExternal'/'writeExternal'), which already stores these values as bytes.

Sorry, that is correct. Jumped the gun too soon

[RogerRiggs]

Its recommended to set the assignee of a issue before starting working and to mark it in progress.
@gauthamkrishnanibm Please make the necessary changes to the issue to let people know you are working on it.

[gauthamkrishnanibm]

@RogerRiggs
Sorry. I am not having write access to JBS as I just started contributing.
Should I discuss about the change in mailing list ?

[RogerRiggs]

I hope you've found The OpenJDK Developers' Guide, its a good read to know what to expect and what is expected of contributors.
Feel free to ask on the mail alias about how things work. If you found the issue you would have seen it was already assigned and it would be appropriate to ask.

Please continue.
As with any modification, its important to identify the tests that validate the change. In this case, the tests are in the repo under test/jdk/java/time.