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

@@ -23,15 +23,22 @@
  * questions.
  */
 
 package sun.util.locale.provider;
 
+import java.util.List;
+import java.util.Locale;
 import sun.util.resources.LocaleData;
 
 /**
  * Accessor for LocaleData
  *
  * @author Naoto Sato
  */
 public interface ResourceBundleBasedAdapter {
     public LocaleData getLocaleData();
+
+    /**
+     * candidate locales customization
+     */
+    public List<Locale> getCandidateLocales(String baseName, Locale locale);
 }