Use Locale.ROOT for locale neutral, case insensitive comparisons

integration-tests/src/test/java/org/springframework/context/annotation/jsr330/ClassPathBeanDefinitionScannerJsr330ScopeIntegrationTests.java

@@ -316,7 +316,7 @@ private ApplicationContext createContext(final ScopedProxyMode scopedProxyMode)
 						break;
 					}
 					else if (annDef.getMetadata().getMetaAnnotationTypes(type).contains(javax.inject.Scope.class.getName())) {
-						metadata.setScopeName(type.substring(type.length() - 13, type.length() - 6).toLowerCase());
+						metadata.setScopeName(type.substring(type.length() - 13, type.length() - 6).toLowerCase(Locale.ROOT));
 						metadata.setScopedProxyMode(scopedProxyMode);
 						break;
 					}

spring-beans/src/main/java/org/springframework/beans/support/PropertyComparator.java

@@ -77,8 +77,8 @@ public int compare(T o1, T o2) {
 		Object v1 = getPropertyValue(o1);
 		Object v2 = getPropertyValue(o2);
 		if (this.sortDefinition.isIgnoreCase() && (v1 instanceof String) && (v2 instanceof String)) {
-			v1 = ((String) v1).toLowerCase();
-			v2 = ((String) v2).toLowerCase();
+			v1 = ((String) v1).toLowerCase(Locale.ROOT);
+			v2 = ((String) v2).toLowerCase(Locale.ROOT);
 		}
 
 		int result;

spring-beans/src/test/java/org/springframework/beans/factory/config/PropertyResourceConfigurerTests.java

@@ -277,7 +277,7 @@ public void testPropertyOverrideConfigurerWithInvalidKey() {
 			}
 			catch (BeanInitializationException ex) {
 				// prove that the processor chokes on the invalid key
-				assertThat(ex.getMessage().toLowerCase().contains("argh")).isTrue();
+				assertThat(ex.getMessage().toLowerCase(Locale.ROOT).contains("argh")).isTrue();
 			}
 		}
 	}

spring-context-support/src/main/java/org/springframework/scheduling/quartz/LocalDataSourceJobStore.java

@@ -155,7 +155,7 @@ public void initialize() {
 			String productName = JdbcUtils.extractDatabaseMetaData(this.dataSource,
 					DatabaseMetaData::getDatabaseProductName);
 			productName = JdbcUtils.commonDatabaseName(productName);
-			if (productName != null && productName.toLowerCase().contains("hsql")) {
+			if (productName != null && productName.toLowerCase(Locale.ROOT).contains("hsql")) {
 				setUseDBLocks(false);
 				setLockHandler(new SimpleSemaphore());
 			}

spring-context/src/main/java/org/springframework/validation/DataBinder.java

@@ -23,6 +23,7 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 
 import org.apache.commons.logging.Log;
@@ -464,7 +465,7 @@ public String[] getAllowedFields() {
 	 * <p>The default implementation of this method stores disallowed field patterns
 	 * in {@linkplain PropertyAccessorUtils#canonicalPropertyName(String) canonical}
 	 * form. As of Spring Framework 5.2.21, the default implementation also transforms
-	 * disallowed field patterns to {@linkplain String#toLowerCase() lowercase} to
+	 * disallowed field patterns to {@linkplain String#toLowerCase(Locale.ROOT) lowercase} to
 	 * support case-insensitive pattern matching in {@link #isAllowed}. Subclasses
 	 * which override this method must therefore take both of these transformations
 	 * into account.
@@ -482,7 +483,8 @@ public void setDisallowedFields(@Nullable String... disallowedFields) {
 		else {
 			String[] fieldPatterns = new String[disallowedFields.length];
 			for (int i = 0; i < fieldPatterns.length; i++) {
-				fieldPatterns[i] = PropertyAccessorUtils.canonicalPropertyName(disallowedFields[i]).toLowerCase();
+				String field = PropertyAccessorUtils.canonicalPropertyName(disallowedFields[i]);
+				fieldPatterns[i] = field.toLowerCase(Locale.ROOT);
 			}
 			this.disallowedFields = fieldPatterns;
 		}
@@ -825,7 +827,7 @@ protected boolean isAllowed(String field) {
 		String[] allowed = getAllowedFields();
 		String[] disallowed = getDisallowedFields();
 		return ((ObjectUtils.isEmpty(allowed) || PatternMatchUtils.simpleMatch(allowed, field)) &&
-				(ObjectUtils.isEmpty(disallowed) || !PatternMatchUtils.simpleMatch(disallowed, field.toLowerCase())));
+				(ObjectUtils.isEmpty(disallowed) || !PatternMatchUtils.simpleMatch(disallowed, field.toLowerCase(Locale.ROOT))));
 	}
 
 	/**

spring-context/src/main/kotlin/org/springframework/context/support/BeanDefinitionDsl.kt

@@ -178,7 +178,7 @@ open class BeanDefinitionDsl internal constructor (private val init: BeanDefinit
 									  role: Role? = null) {
 
 		val customizer = BeanDefinitionCustomizer { bd ->
-			scope?.let { bd.scope = scope.name.toLowerCase() }
+			scope?.let { bd.scope = scope.name.toLowerCase(Locale.ROOT) }
 			isLazyInit?.let { bd.isLazyInit = isLazyInit }
 			isPrimary?.let { bd.isPrimary = isPrimary }
 			isAutowireCandidate?.let { bd.isAutowireCandidate = isAutowireCandidate }
@@ -221,7 +221,7 @@ open class BeanDefinitionDsl internal constructor (private val init: BeanDefinit
 									  crossinline function: BeanSupplierContext.() -> T) {
 
 		val customizer = BeanDefinitionCustomizer { bd ->
-			scope?.let { bd.scope = scope.name.toLowerCase() }
+			scope?.let { bd.scope = scope.name.toLowerCase(Locale.ROOT) }
 			isLazyInit?.let { bd.isLazyInit = isLazyInit }
 			isPrimary?.let { bd.isPrimary = isPrimary }
 			isAutowireCandidate?.let { bd.isAutowireCandidate = isAutowireCandidate }

spring-core/src/main/java/org/springframework/core/convert/support/StringToBooleanConverter.java

@@ -55,7 +55,7 @@ public Boolean convert(String source) {
 		if (value.isEmpty()) {
 			return null;
 		}
-		value = value.toLowerCase();
+		value = value.toLowerCase(Locale.ROOT);
 		if (trueValues.contains(value)) {
 			return Boolean.TRUE;
 		}

spring-core/src/main/java/org/springframework/util/MimeType.java

@@ -182,10 +182,10 @@ public MimeType(String type, String subtype, @Nullable Map<String, String> param
 		Assert.hasLength(subtype, "'subtype' must not be empty");
 		checkToken(type);
 		checkToken(subtype);
-		this.type = type.toLowerCase(Locale.ENGLISH);
-		this.subtype = subtype.toLowerCase(Locale.ENGLISH);
+		this.type = type.toLowerCase(Locale.ROOT);
+		this.subtype = subtype.toLowerCase(Locale.ROOT);
 		if (!CollectionUtils.isEmpty(parameters)) {
-			Map<String, String> map = new LinkedCaseInsensitiveMap<>(parameters.size(), Locale.ENGLISH);
+			Map<String, String> map = new LinkedCaseInsensitiveMap<>(parameters.size(), Locale.ROOT);
 			parameters.forEach((parameter, value) -> {
 				checkParameters(parameter, value);
 				map.put(parameter, value);

spring-core/src/main/java/org/springframework/util/ResourceUtils.java

@@ -295,7 +295,7 @@ public static boolean isJarURL(URL url) {
 	 */
 	public static boolean isJarFileURL(URL url) {
 		return (URL_PROTOCOL_FILE.equals(url.getProtocol()) &&
-				url.getPath().toLowerCase().endsWith(JAR_FILE_EXTENSION));
+				url.getPath().toLowerCase(Locale.ROOT).endsWith(JAR_FILE_EXTENSION));
 	}
 
 	/**

spring-core/src/test/java/org/springframework/core/annotation/MergedAnnotationsTests.java

@@ -2947,7 +2947,7 @@ enum RequestMethod {
 		 */
 		@Override
 		public String toString() {
-			return "method: " + name().toLowerCase();
+			return "method: " + name().toLowerCase(Locale.ROOT);
 		}
 	}
 

spring-expression/src/main/java/org/springframework/expression/spel/standard/InternalSpelExpressionParser.java

@@ -750,7 +750,7 @@ private SpelNodeImpl eatPossiblyQualifiedId() {
 				throw internalException( this.expressionString.length(), SpelMessage.OOD);
 			}
 			throw internalException(node.startPos, SpelMessage.NOT_EXPECTED_TOKEN,
-					"qualified ID", node.getKind().toString().toLowerCase());
+					"qualified ID", node.getKind().toString().toLowerCase(Locale.ROOT));
 		}
 		return new QualifiedIdentifier(qualifiedIdPieces.getFirst().getStartPosition(),
 				qualifiedIdPieces.getLast().getEndPosition(), qualifiedIdPieces.toArray(new SpelNodeImpl[0]));
@@ -942,7 +942,7 @@ private Token eatToken(TokenKind expectedKind) {
 		}
 		if (t.kind != expectedKind) {
 			throw internalException(t.startPos, SpelMessage.NOT_EXPECTED_TOKEN,
-					expectedKind.toString().toLowerCase(), t.getKind().toString().toLowerCase());
+					expectedKind.toString().toLowerCase(Locale.ROOT), t.getKind().toString().toLowerCase(Locale.ROOT));
 		}
 		return t;
 	}
@@ -1038,7 +1038,7 @@ public String toString(@Nullable Token t) {
 		if (t.getKind().hasPayload()) {
 			return t.stringValue();
 		}
-		return t.kind.toString().toLowerCase();
+		return t.kind.toString().toLowerCase(Locale.ROOT);
 	}
 
 	private void checkOperands(Token token, @Nullable SpelNodeImpl left, @Nullable SpelNodeImpl right) {

spring-expression/src/test/java/org/springframework/expression/spel/MethodInvocationTests.java

@@ -60,7 +60,7 @@ public void testSimpleAccess01() {
 	public void testStringClass() {
 		evaluate("new java.lang.String('hello').charAt(2)", 'l', Character.class);
 		evaluate("new java.lang.String('hello').charAt(2).equals('l'.charAt(0))", true, Boolean.class);
-		evaluate("'HELLO'.toLowerCase()", "hello", String.class);
+		evaluate("'HELLO'.toLowerCase(Locale.ROOT)", "hello", String.class);
 		evaluate("'   abcba '.trim()", "abcba", String.class);
 	}
 

spring-expression/src/test/java/org/springframework/expression/spel/SpelCompilationCoverageTests.java

@@ -3768,7 +3768,7 @@ public void constructorReference_SPR13781() {
 
 		// The actual expression from the bug report. It fails if the ENGLISH reference fails
 		// to pop the type reference for Locale off the stack (if it isn't popped then
-		// toLowerCase() will be called with a Locale parameter). In this situation the
+		// toLowerCase(Locale.ROOT) will be called with a Locale parameter). In this situation the
 		// code generation for ENGLISH should notice there is something on the stack that
 		// is not required and pop it off.
 		expression = parser.parseExpression("#userId.toString().toLowerCase(T(java.util.Locale).ENGLISH)");

spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/CallMetaDataContext.java

@@ -385,7 +385,7 @@ protected List<SqlParameter> reconcileParameters(List<SqlParameter> parameters)
 				if (meta.isReturnParameter()) {
 					param = declaredParams.get(getFunctionReturnName());
 					if (param == null && !getOutParameterNames().isEmpty()) {
-						param = declaredParams.get(getOutParameterNames().get(0).toLowerCase());
+						param = declaredParams.get(getOutParameterNames().get(0).toLowerCase(Locale.ROOT));
 					}
 					if (param == null) {
 						throw new InvalidDataAccessApiUsageException(
@@ -488,15 +488,15 @@ public Map<String, Object> matchInParameterValuesWithCallParameters(SqlParameter
 				String parameterName = parameter.getName();
 				String parameterNameToMatch = obtainMetaDataProvider().parameterNameToUse(parameterName);
 				if (parameterNameToMatch != null) {
-					callParameterNames.put(parameterNameToMatch.toLowerCase(), parameterName);
+					callParameterNames.put(parameterNameToMatch.toLowerCase(Locale.ROOT), parameterName);
 				}
 				if (parameterName != null) {
 					if (parameterSource.hasValue(parameterName)) {
 						matchedParameters.put(parameterName,
 								SqlParameterSourceUtils.getTypedValue(parameterSource, parameterName));
 					}
 					else {
-						String lowerCaseName = parameterName.toLowerCase();
+						String lowerCaseName = parameterName.toLowerCase(Locale.ROOT);
 						if (parameterSource.hasValue(lowerCaseName)) {
 							matchedParameters.put(parameterName,
 									SqlParameterSourceUtils.getTypedValue(parameterSource, lowerCaseName));
@@ -556,7 +556,7 @@ else if (logger.isInfoEnabled()) {
 				String parameterName = parameter.getName();
 				String parameterNameToMatch = provider.parameterNameToUse(parameterName);
 				if (parameterNameToMatch != null) {
-					callParameterNames.put(parameterNameToMatch.toLowerCase(), parameterName);
+					callParameterNames.put(parameterNameToMatch.toLowerCase(Locale.ROOT), parameterName);
 				}
 			}
 		}
@@ -680,7 +680,7 @@ protected String createParameterBinding(SqlParameter parameter) {
 	}
 
 	private static String lowerCase(@Nullable String paramName) {
-		return (paramName != null ? paramName.toLowerCase() : "");
+		return (paramName != null ? paramName.toLowerCase(Locale.ROOT) : "");
 	}
 
 }

spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/GenericCallMetaDataProvider.java

@@ -282,7 +282,7 @@ else if (isStoresUpperCaseIdentifiers()) {
 			return identifierName.toUpperCase();
 		}
 		else if (isStoresLowerCaseIdentifiers()) {
-			return identifierName.toLowerCase();
+			return identifierName.toLowerCase(Locale.ROOT);
 		}
 		else {
 			return identifierName;

spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/GenericTableMetaDataProvider.java

@@ -233,7 +233,7 @@ else if (isStoresUpperCaseIdentifiers()) {
 			return tableName.toUpperCase();
 		}
 		else if (isStoresLowerCaseIdentifiers()) {
-			return tableName.toLowerCase();
+			return tableName.toLowerCase(Locale.ROOT);
 		}
 		else {
 			return tableName;
@@ -250,7 +250,7 @@ else if (isStoresUpperCaseIdentifiers()) {
 			return catalogName.toUpperCase();
 		}
 		else if (isStoresLowerCaseIdentifiers()) {
-			return catalogName.toLowerCase();
+			return catalogName.toLowerCase(Locale.ROOT);
 		}
 		else {
 			return catalogName;
@@ -267,7 +267,7 @@ else if (isStoresUpperCaseIdentifiers()) {
 			return schemaName.toUpperCase();
 		}
 		else if (isStoresLowerCaseIdentifiers()) {
-			return schemaName.toLowerCase();
+			return schemaName.toLowerCase(Locale.ROOT);
 		}
 		else {
 			return schemaName;

spring-jdbc/src/main/java/org/springframework/jdbc/core/metadata/TableMetaDataContext.java

@@ -218,7 +218,7 @@ public List<Object> matchInParameterValuesWithInsertColumns(SqlParameterSource p
 				values.add(SqlParameterSourceUtils.getTypedValue(parameterSource, column));
 			}
 			else {
-				String lowerCaseName = column.toLowerCase();
+				String lowerCaseName = column.toLowerCase(Locale.ROOT);
 				if (parameterSource.hasValue(lowerCaseName)) {
 					values.add(SqlParameterSourceUtils.getTypedValue(parameterSource, lowerCaseName));
 				}
@@ -251,7 +251,7 @@ public List<Object> matchInParameterValuesWithInsertColumns(Map<String, ?> inPar
 		for (String column : this.tableColumns) {
 			Object value = inParameters.get(column);
 			if (value == null) {
-				value = inParameters.get(column.toLowerCase());
+				value = inParameters.get(column.toLowerCase(Locale.ROOT));
 				if (value == null) {
 					for (Map.Entry<String, ?> entry : inParameters.entrySet()) {
 						if (column.equalsIgnoreCase(entry.getKey())) {

spring-jdbc/src/main/java/org/springframework/jdbc/core/namedparam/SqlParameterSourceUtils.java

@@ -115,7 +115,7 @@ public static Map<String, String> extractCaseInsensitiveParameterNames(SqlParame
 		String[] paramNames = parameterSource.getParameterNames();
 		if (paramNames != null) {
 			for (String name : paramNames) {
-				caseInsensitiveParameterNames.put(name.toLowerCase(), name);
+				caseInsensitiveParameterNames.put(name.toLowerCase(Locale.ROOT), name);
 			}
 		}
 		return caseInsensitiveParameterNames;

spring-messaging/src/test/java/org/springframework/messaging/simp/stomp/StompHeaderAccessorTests.java

@@ -190,7 +190,7 @@ public void modifyCustomNativeHeader() {
 
 		StompHeaderAccessor headers = StompHeaderAccessor.create(StompCommand.SUBSCRIBE, extHeaders);
 		String accountId = headers.getFirstNativeHeader("accountId");
-		headers.setNativeHeader("accountId", accountId.toLowerCase());
+		headers.setNativeHeader("accountId", accountId.toLowerCase(Locale.ROOT));
 
 		Map<String, List<String>> actual = headers.toNativeHeaderMap();
 		assertThat(actual.size()).isEqualTo(3);

spring-test/src/main/java/org/springframework/mock/web/MockHttpServletRequest.java

@@ -406,7 +406,8 @@ public void setCharacterEncoding(@Nullable String characterEncoding) {
 	private void updateContentTypeHeader() {
 		if (StringUtils.hasLength(this.contentType)) {
 			String value = this.contentType;
-			if (StringUtils.hasLength(this.characterEncoding) && !this.contentType.toLowerCase().contains(CHARSET_PREFIX)) {
+			if (StringUtils.hasLength(this.characterEncoding) &&
+					!this.contentType.toLowerCase(Locale.ROOT).contains(CHARSET_PREFIX)) {
 				value += ';' + CHARSET_PREFIX + this.characterEncoding;
 			}
 			doAddHeaderValue(HttpHeaders.CONTENT_TYPE, value, true);
@@ -484,7 +485,7 @@ public void setContentType(@Nullable String contentType) {
 			}
 			catch (IllegalArgumentException ex) {
 				// Try to get charset value anyway
-				int charsetIndex = contentType.toLowerCase().indexOf(CHARSET_PREFIX);
+				int charsetIndex = contentType.toLowerCase(Locale.ROOT).indexOf(CHARSET_PREFIX);
 				if (charsetIndex != -1) {
 					this.characterEncoding = contentType.substring(charsetIndex + CHARSET_PREFIX.length());
 				}

spring-test/src/main/java/org/springframework/mock/web/MockHttpServletResponse.java

@@ -215,7 +215,7 @@ private void setExplicitCharacterEncoding(String characterEncoding) {
 	private void updateContentTypePropertyAndHeader() {
 		if (this.contentType != null) {
 			String value = this.contentType;
-			if (this.characterEncodingSet && !value.toLowerCase().contains(CHARSET_PREFIX)) {
+			if (this.characterEncodingSet && !value.toLowerCase(Locale.ROOT).contains(CHARSET_PREFIX)) {
 				value += ';' + CHARSET_PREFIX + getCharacterEncoding();
 				this.contentType = value;
 			}
@@ -315,7 +315,7 @@ public void setContentType(@Nullable String contentType) {
 			}
 			catch (Exception ex) {
 				// Try to get charset value anyway
-				int charsetIndex = contentType.toLowerCase().indexOf(CHARSET_PREFIX);
+				int charsetIndex = contentType.toLowerCase(Locale.ROOT).indexOf(CHARSET_PREFIX);
 				if (charsetIndex != -1) {
 					setExplicitCharacterEncoding(contentType.substring(charsetIndex + CHARSET_PREFIX.length()));
 				}

spring-test/src/main/java/org/springframework/test/context/junit/jupiter/AbstractExpressionEvaluatingCondition.java

@@ -49,7 +49,7 @@
  *
  * <ul>
  * <li>Spring Expression Language (SpEL) expression &mdash; for example:
- * <pre style="code">#{systemProperties['os.name'].toLowerCase().contains('mac')}</pre>
+ * <pre style="code">#{systemProperties['os.name'].toLowerCase(Locale.ROOT).contains('mac')}</pre>
  * <li>Placeholder for a property available in the Spring
  * {@link org.springframework.core.env.Environment Environment} &mdash; for example:
  * <pre style="code">${smoke.tests.enabled}</pre>
@@ -193,7 +193,7 @@ private <A extends Annotation> boolean evaluateExpression(String expression, boo
 			return (Boolean) result;
 		}
 		else if (result instanceof String) {
-			String str = ((String) result).trim().toLowerCase();
+			String str = ((String) result).trim().toLowerCase(Locale.ROOT);
 			if ("true".equals(str)) {
 				return true;
 			}

spring-test/src/main/java/org/springframework/test/context/junit/jupiter/DisabledIf.java

@@ -44,7 +44,7 @@
  * {@literal @}Target({ElementType.TYPE, ElementType.METHOD})
  * {@literal @}Retention(RetentionPolicy.RUNTIME)
  * {@literal @}DisabledIf(
- *     expression = "#{systemProperties['os.name'].toLowerCase().contains('mac')}",
+ *     expression = "#{systemProperties['os.name'].toLowerCase(Locale.ROOT).contains('mac')}",
  *     reason = "Disabled on Mac OS"
  * )
  * public {@literal @}interface DisabledOnMac {}
@@ -94,7 +94,7 @@
 	 *
 	 * <ul>
 	 * <li>Spring Expression Language (SpEL) expression &mdash; for example:
-	 * <pre style="code">@DisabledIf("#{systemProperties['os.name'].toLowerCase().contains('mac')}")</pre>
+	 * <pre style="code">@DisabledIf("#{systemProperties['os.name'].toLowerCase(Locale.ROOT).contains('mac')}")</pre>
 	 * <li>Placeholder for a property available in the Spring
 	 * {@link org.springframework.core.env.Environment Environment} &mdash; for example:
 	 * <pre style="code">@DisabledIf("${smoke.tests.disabled}")</pre>

spring-test/src/main/java/org/springframework/test/context/junit/jupiter/EnabledIf.java

@@ -44,7 +44,7 @@
  * {@literal @}Target({ElementType.TYPE, ElementType.METHOD})
  * {@literal @}Retention(RetentionPolicy.RUNTIME)
  * {@literal @}EnabledIf(
- *     expression = "#{systemProperties['os.name'].toLowerCase().contains('mac')}",
+ *     expression = "#{systemProperties['os.name'].toLowerCase(Locale.ROOT).contains('mac')}",
  *     reason = "Enabled on Mac OS"
  * )
  * public {@literal @}interface EnabledOnMac {}
@@ -93,7 +93,7 @@
 	 *
 	 * <ul>
 	 * <li>Spring Expression Language (SpEL) expression &mdash; for example:
-	 * <pre style="code">@EnabledIf("#{systemProperties['os.name'].toLowerCase().contains('mac')}")</pre>
+	 * <pre style="code">@EnabledIf("#{systemProperties['os.name'].toLowerCase(Locale.ROOT).contains('mac')}")</pre>
 	 * <li>Placeholder for a property available in the Spring
 	 * {@link org.springframework.core.env.Environment Environment} &mdash; for example:
 	 * <pre style="code">@EnabledIf("${smoke.tests.enabled}")</pre>

spring-test/src/test/java/org/springframework/test/context/TestContextAnnotationUtilsTests.java

@@ -77,7 +77,7 @@ void standardDefaultMode() {
 
 		@Test
 		void overriddenDefaultMode() {
-			setGlobalFlag("\t" + OVERRIDE.name().toLowerCase() + "   ");
+			setGlobalFlag("\t" + OVERRIDE.name().toLowerCase(Locale.ROOT) + "   ");
 			assertThat(searchEnclosingClass(OuterTestCase.class)).isFalse();
 			assertThat(searchEnclosingClass(OuterTestCase.NestedTestCase.class)).isFalse();
 			assertThat(searchEnclosingClass(OuterTestCase.NestedTestCase.DoubleNestedTestCase.class)).isFalse();