Honor overridden AcceptHeaderLocaleContextResolver.getDefaultLocale()

Closes gh-24871

spring-web/src/main/java/org/springframework/web/server/i18n/AcceptHeaderLocaleContextResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -39,6 +39,7 @@ import org.springframework.web.server.ServerWebExchange;
  * @author Sebastien Deleuze
  * @author Juergen Hoeller
  * @since 5.0
+ * @see HttpHeaders#getAcceptLanguageAsLocales()
  */
 public class AcceptHeaderLocaleContextResolver implements LocaleContextResolver {
 
@@ -76,6 +77,7 @@ public class AcceptHeaderLocaleContextResolver implements LocaleContextResolver
 
 	/**
 	 * The configured default locale, if any.
+	 * <p>This method may be overridden in subclasses.
 	 */
 	@Nullable
 	public Locale getDefaultLocale() {
@@ -98,7 +100,7 @@ public class AcceptHeaderLocaleContextResolver implements LocaleContextResolver
 	@Nullable
 	private Locale resolveSupportedLocale(@Nullable List<Locale> requestLocales) {
 		if (CollectionUtils.isEmpty(requestLocales)) {
-			return this.defaultLocale;  // may be null
+			return getDefaultLocale();  // may be null
 		}
 		List<Locale> supportedLocales = getSupportedLocales();
 		if (supportedLocales.isEmpty()) {
@@ -128,7 +130,8 @@ public class AcceptHeaderLocaleContextResolver implements LocaleContextResolver
 			return languageMatch;
 		}
 
-		return (this.defaultLocale != null ? this.defaultLocale : requestLocales.get(0));
+		Locale defaultLocale = getDefaultLocale();
+		return (defaultLocale != null ? defaultLocale : requestLocales.get(0));
 	}
 
 	@Override

spring-webmvc/src/main/java/org/springframework/web/servlet/i18n/AcceptHeaderLocaleResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -83,6 +83,7 @@ public class AcceptHeaderLocaleResolver implements LocaleResolver {
 
 	/**
 	 * The configured default locale, if any.
+	 * <p>This method may be overridden in subclasses.
 	 * @since 4.3
 	 */
 	@Nullable