8355522: Remove the java.locale.useOldISOCodes system property

src/java.base/share/classes/java/util/Locale.java

@@ -528,34 +528,13 @@
  *
  * <h3><a id="legacy_language_codes">Legacy language codes</a></h3>
  *
- * <p>Locale's constructors have always converted three language codes to
- * their earlier, obsoleted forms: {@code he} maps to {@code iw},
- * {@code yi} maps to {@code ji}, and {@code id} maps to
- * {@code in}. Since Java SE 17, this is no longer the case. Each
- * language maps to its new form; {@code iw} maps to {@code he}, {@code ji}
- * maps to {@code yi}, and {@code in} maps to {@code id}.
- *
- * <p>For backwards compatible behavior, the system property
- * {@systemProperty java.locale.useOldISOCodes} reverts the behavior
- * back to that of before Java SE 17. If the system property is set to
- * {@code true}, those three current language codes are mapped to their
- * backward compatible forms. The property is only read at Java runtime
- * startup and subsequent calls to {@code System.setProperty()} will
- * have no effect. <b>As of Java SE 25, the use of the
- * {@code java.locale.useOldISOCodes} system property is deprecated.
- * This backwards compatible behavior will be removed in a future release
- * of the JDK.</b>
- *
- * <p>The APIs added in Java SE 7 map between the old and new language codes,
- * maintaining the mapped codes internal to Locale (so that
- * {@code getLanguage} and {@code toString} reflect the mapped
- * code, which depends on the {@code java.locale.useOldISOCodes} system
- * property), but using the new codes in the BCP 47 language tag APIs (so
- * that {@code toLanguageTag} reflects the new one). This
- * preserves the equivalence between Locales no matter which code or
- * API is used to construct them. Java's default resource bundle
- * lookup mechanism also implements this mapping, so that resources
- * can be named using either convention, see {@link ResourceBundle.Control}.
+ * <p>For compatibility, a {@code Locale} created with one of the
+ * three obsolete language codes, {@code iw}, {@code ji}, or {@code in},
+ * will map the language to its modern equivalent, {@code he}, {@code yi},
+ * or {@code id}, respectively.
+ * <p>The default resource bundle lookup mechanism also implements
+ * this mapping, so that resources can be named using either convention,
+ * see {@link ResourceBundle.Control}.
  *
  * @spec https://www.rfc-editor.org/info/rfc4647
  *      RFC 4647: Matching of Language Tags
@@ -2517,8 +2496,7 @@ private Object readResolve() throws java.io.ObjectStreamException {
 
     private static String convertOldISOCodes(String language) {
         // we accept both the old and the new ISO codes for the languages whose ISO
-        // codes have changed, but we always store the NEW code, unless the property
-        // java.locale.useOldISOCodes is set to "true"
+        // codes have changed, but we always store the NEW code
         return BaseLocale.convertOldISOCodes(LocaleUtils.toLowerString(language).intern());
     }
 

src/java.base/share/classes/jdk/internal/util/StaticProperty.java

@@ -53,7 +53,6 @@ public final class StaticProperty {
     private static final String STDOUT_ENCODING;
     private static final String SUN_JNU_ENCODING;
     private static final String JAVA_PROPERTIES_DATE;
-    private static final String JAVA_LOCALE_USE_OLD_ISO_CODES;
     private static final String OS_NAME;
     private static final String OS_ARCH;
     private static final String OS_VERSION;
@@ -94,7 +93,6 @@ private StaticProperty() {}
         STDOUT_ENCODING = getProperty(props, "stdout.encoding");
         SUN_JNU_ENCODING = getProperty(props, "sun.jnu.encoding");
         JAVA_PROPERTIES_DATE = getProperty(props, "java.properties.date", null);
-        JAVA_LOCALE_USE_OLD_ISO_CODES = getProperty(props, "java.locale.useOldISOCodes", "");
         OS_NAME = getProperty(props, "os.name");
         OS_ARCH = getProperty(props, "os.arch");
         OS_VERSION = getProperty(props, "os.version");
@@ -258,13 +256,6 @@ public static String javaPropertiesDate() {
         return JAVA_PROPERTIES_DATE;
     }
 
-    /**
-     * {@return the {@code java.locale.useOldISOCodes} system property}
-     */
-    public static String javaLocaleUseOldISOCodes() {
-        return JAVA_LOCALE_USE_OLD_ISO_CODES;
-    }
-
      /**
       * {@return the {@code os.name} system property}
       */

src/java.base/share/classes/sun/util/locale/BaseLocale.java

@@ -34,7 +34,6 @@
 
 import jdk.internal.misc.CDS;
 import jdk.internal.util.ReferencedKeySet;
-import jdk.internal.util.StaticProperty;
 import jdk.internal.vm.annotation.Stable;
 
 import java.util.StringJoiner;
@@ -110,16 +109,14 @@ public ReferencedKeySet<BaseLocale> get() {
     private @Stable int hash;
 
     /**
-     * Boolean for the old ISO language code compatibility.
-     * The system property "java.locale.useOldISOCodes" is not security sensitive,
-     * so no need to ensure privileged access here.
+     * Emit the warning message if the system property "java.locale.useOldISOCodes" is
+     * specified.
      */
-    private static final boolean OLD_ISO_CODES = StaticProperty.javaLocaleUseOldISOCodes()
-            .equalsIgnoreCase("true");
     static {
-        if (OLD_ISO_CODES) {
-            System.err.println("WARNING: The use of the system property \"java.locale.useOldISOCodes\"" +
-                " is deprecated. It will be removed in a future release of the JDK.");
+        if (!System.getProperty("java.locale.useOldISOCodes", "").isEmpty()) {
+            System.err.println("WARNING: The system property" +
+                " \"java.locale.useOldISOCodes\" is no longer supported." +
+                " Any specified value will be ignored.");
         }
     }
 
@@ -166,7 +163,8 @@ public static BaseLocale getInstance(String language, String script,
             }
         }
 
-        // JDK uses deprecated ISO639.1 language codes for he, yi and id
+        // Normalize deprecated ISO 639-1 language codes for Hebrew, Yiddish,
+        // and Indonesian to their current standard forms.
         if (!language.isEmpty()) {
             language = convertOldISOCodes(language);
         }
@@ -183,9 +181,9 @@ public static BaseLocale getInstance(String language, String script,
 
     public static String convertOldISOCodes(String language) {
         return switch (language) {
-            case "he", "iw" -> OLD_ISO_CODES ? "iw" : "he";
-            case "id", "in" -> OLD_ISO_CODES ? "in" : "id";
-            case "yi", "ji" -> OLD_ISO_CODES ? "ji" : "yi";
+            case "iw" -> "he";
+            case "in" -> "id";
+            case "ji" -> "yi";
             default -> language;
         };
     }

src/java.base/share/classes/sun/util/locale/provider/LocaleResources.java

@@ -62,7 +62,6 @@
 import java.util.regex.Pattern;
 import java.util.stream.Stream;
 
-import jdk.internal.util.StaticProperty;
 import sun.util.resources.LocaleData;
 import sun.util.resources.OpenListResourceBundle;
 import sun.util.resources.TimeZoneNamesBundle;
@@ -288,16 +287,6 @@ public String getCurrencyName(String key) {
     }
 
     public String getLocaleName(String key) {
-        // Get names for old ISO codes with new ISO code resources
-        if (StaticProperty.javaLocaleUseOldISOCodes().equalsIgnoreCase("true")) {
-            key = switch (key) {
-                case "iw" -> "he";
-                case "in" -> "id";
-                case "ji" -> "yi";
-                default -> key;
-            };
-        }
-
         Object localeName = null;
         String cacheKey = LOCALE_NAMES + key;
 

test/jdk/java/util/Locale/LocaleTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2007, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,7 +26,7 @@
  * 4118587 4118595 4122371 4126371 4126880 4135316 4135752 4139504 4139940 4143951
  * 4147315 4147317 4147552 4335196 4778440 4940539 5010672 6475525 6544471 6627549
  * 6786276 7066203 7085757 8008577 8030696 8170840 8174269 8255086 8263202 8287868
- * 8337603
+ * 8337603 8355522
  * @summary test Locales
  * @modules jdk.localedata
  * @run junit LocaleTest
@@ -709,34 +709,18 @@ public void TestChangedISO639Codes() {
         Locale indonesianOld = Locale.of("in");
         Locale indonesianNew = Locale.of("id");
 
-        if ("true".equalsIgnoreCase(System.getProperty("java.locale.useOldISOCodes"))) {
-            if (!hebrewNew.getLanguage().equals("iw")) {
-                fail("Got back wrong language code for new Hebrew: expected \"iw\", got \""
-                        + hebrewNew.getLanguage() + "\"");
-            }
-            if (!yiddishNew.getLanguage().equals("ji")) {
-                fail("Got back wrong language code for new Yiddish: expected \"ji\", got \""
-                        + yiddishNew.getLanguage() + "\"");
-            }
-            if (!indonesianNew.getLanguage().equals("in")) {
-                fail("Got back wrong language code for new Indonesian: expected \"in\", got \""
-                        + indonesianNew.getLanguage() + "\"");
-            }
-        } else {
-            if (!hebrewOld.getLanguage().equals("he")) {
-                fail("Got back wrong language code for old Hebrew: expected \"he\", got \""
-                        + hebrewNew.getLanguage() + "\"");
-            }
-            if (!yiddishOld.getLanguage().equals("yi")) {
-                fail("Got back wrong language code for old Yiddish: expected \"yi\", got \""
-                        + yiddishNew.getLanguage() + "\"");
-            }
-            if (!indonesianOld.getLanguage().equals("id")) {
-                fail("Got back wrong language code for old Indonesian: expected \"id\", got \""
-                        + indonesianNew.getLanguage() + "\"");
-            }
+        if (!hebrewOld.getLanguage().equals("he")) {
+            fail("Got back wrong language code for old Hebrew: expected \"he\", got \""
+                    + hebrewNew.getLanguage() + "\"");
+        }
+        if (!yiddishOld.getLanguage().equals("yi")) {
+            fail("Got back wrong language code for old Yiddish: expected \"yi\", got \""
+                    + yiddishNew.getLanguage() + "\"");
+        }
+        if (!indonesianOld.getLanguage().equals("id")) {
+            fail("Got back wrong language code for old Indonesian: expected \"id\", got \""
+                    + indonesianNew.getLanguage() + "\"");
         }
-
     }
 
     /**

test/jdk/java/util/Locale/UseOldISOCodesTest.java

@@ -23,7 +23,7 @@
 
 /*
  * @test
- * @bug 8295232 8353118
+ * @bug 8295232 8353118 8355522
  * @summary Tests for the "java.locale.useOldISOCodes" system property
  * @library /test/lib
  * @run junit UseOldISOCodesTest
@@ -34,7 +34,7 @@
 
 import org.junit.jupiter.api.Test;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
 
 public class UseOldISOCodesTest {
 
@@ -44,20 +44,17 @@ public void testUseOldISOCodes() throws Exception {
                 .outputTo(System.out)
                 .errorTo(System.err);
         oa.shouldHaveExitValue(0);
-        oa.stderrShouldMatch("WARNING: The use of the system property \"java.locale.useOldISOCodes\" is deprecated. It will be removed in a future release of the JDK.");
+        oa.stderrShouldMatch("WARNING: The system property \"java.locale.useOldISOCodes\" is no longer supported. Any specified value will be ignored.");
     }
 
     static class Runner {
         private static final String obsoleteCode = "iw";
         private static final String newCode = "he";
 
         public static void main(String[] args) {
-            // Ensure java.locale.useOldISOCodes is only interpreted at runtime startup
-            // Should have no effect
-            System.setProperty("java.locale.useOldISOCodes", "false");
-            Locale locale = Locale.of(newCode);
-            assertEquals(obsoleteCode, locale.getLanguage(),
-                    "newCode 'he' was not mapped to 'iw' with useOldISOCodes=true");
+            // Ensure java.locale.useOldISOCodes should have no effect
+            assertNotEquals(obsoleteCode, Locale.of(newCode).getLanguage(),
+                    "newCode 'he' was mapped to 'iw' with useOldISOCodes=true");
         }
     }
 }