<i18n dev> RFR: 8355522: Remove the `java.locale.useOldISOCodes` system property

[Justin Lu]

On Mon, 21 Jul 2025 22:56:50 GMT, Naoto Sato <naoto at openjdk.org> wrote:

> This PR removes the system property deprecated in JDK 25. If the property is specified at runtime, a warning will be emitted at startup to inform the user that the value is ignored. A corresponding CSR has been drafted as well

Should we also remove the test method, `ModuleTestUtil.runModuleWithLegacyCode` which passes the now defunct property to the process.

test/jdk/java/util/Locale/UseOldISOCodesTest.java line 56:

> 54:         public static void main(String[] args) {
> 55:             // Ensure java.locale.useOldISOCodes should have no effect
> 56:             System.setProperty("java.locale.useOldISOCodes", "false");

IMO, it seems weird to keep this line in the test, even if it has no effect. The original goal was to ensure the property only had impact when set during startup. The current test is no longer concerned with that (since the property no longer performs any mapping).

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PR Review: https://git.openjdk.org/jdk/pull/26419#pullrequestreview-3044862073
PR Review Comment: https://git.openjdk.org/jdk/pull/26419#discussion_r2223817468