Merge branch '3.3.x'

Closes gh-42736

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/type/ImageReference.java

@@ -187,7 +187,7 @@ public final class ImageReference {
 	 */
 	public static ImageReference forJarFile(File jarFile) {
 		String filename = jarFile.getName();
-		Assert.isTrue(filename.toLowerCase().endsWith(".jar"), () -> "File '" + jarFile + "' is not a JAR");
+		Assert.isTrue(filename.toLowerCase(Locale.ROOT).endsWith(".jar"), () -> "File '" + jarFile + "' is not a JAR");
 		filename = filename.substring(0, filename.length() - 4);
 		int firstDot = filename.indexOf('.');
 		if (firstDot == -1) {

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/AbstractBootArchiveIntegrationTests.java

@@ -638,7 +638,7 @@ abstract class AbstractBootArchiveIntegrationTests {
 
 	protected void copyApplication(String name) throws IOException {
 		File output = new File(this.gradleBuild.getProjectDir(),
-				"src/main/java/com/example/" + this.taskName.toLowerCase() + "/" + name);
+				"src/main/java/com/example/" + this.taskName.toLowerCase(Locale.ROOT) + "/" + name);
 		output.mkdirs();
 		FileSystemUtils.copyRecursively(
 				new File("src/test/java/com/example/" + this.taskName.toLowerCase(Locale.ENGLISH) + "/" + name),

spring-boot-project/spring-boot-tools/spring-boot-jarmode-tools/src/main/java/org/springframework/boot/jarmode/tools/Context.java

@@ -25,6 +25,7 @@ import java.net.URLConnection;
 import java.nio.file.Paths;
 import java.security.CodeSource;
 import java.security.ProtectionDomain;
+import java.util.Locale;
 import java.util.jar.JarFile;
 
 import org.springframework.util.Assert;
@@ -67,7 +68,7 @@ class Context {
 	}
 
 	private boolean isJarOrWar(File jarFile) {
-		String name = jarFile.getName().toLowerCase();
+		String name = jarFile.getName().toLowerCase(Locale.ROOT);
 		return name.endsWith(".jar") || name.endsWith(".war");
 	}
 

spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/FileUtils.java

@@ -18,6 +18,7 @@ package org.springframework.boot.loader.tools;
 
 import java.io.File;
 import java.io.IOException;
+import java.util.Locale;
 import java.util.jar.Attributes;
 import java.util.jar.JarFile;
 import java.util.jar.Manifest;
@@ -88,7 +89,7 @@ public abstract class FileUtils {
 	}
 
 	private static boolean isDigestName(Object name) {
-		return String.valueOf(name).toUpperCase().endsWith("-DIGEST");
+		return String.valueOf(name).toUpperCase(Locale.ROOT).endsWith("-DIGEST");
 	}
 
 }

spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/Layer.java

@@ -16,6 +16,7 @@
 
 package org.springframework.boot.loader.tools;
 
+import java.util.Locale;
 import java.util.regex.Pattern;
 
 import org.springframework.util.Assert;
@@ -41,7 +42,7 @@ public class Layer {
 	public Layer(String name) {
 		Assert.hasText(name, "Name must not be empty");
 		Assert.isTrue(PATTERN.matcher(name).matches(), () -> "Malformed layer name '" + name + "'");
-		Assert.isTrue(!name.equalsIgnoreCase("ext") && !name.toLowerCase().startsWith("springboot"),
+		Assert.isTrue(!name.equalsIgnoreCase("ext") && !name.toLowerCase(Locale.ROOT).startsWith("springboot"),
 				() -> "Layer name '" + name + "' is reserved");
 		this.name = name;
 	}

spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/Repackager.java

@@ -19,6 +19,7 @@ package org.springframework.boot.loader.tools;
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.attribute.FileTime;
+import java.util.Locale;
 import java.util.Map;
 import java.util.jar.JarFile;
 
@@ -50,7 +51,7 @@ public class Repackager extends Packager {
 	@Override
 	protected void writeSignatureFileIfNecessary(Map<String, Library> writtenLibraries, AbstractJarWriter writer)
 			throws IOException {
-		if (getSource().getName().toLowerCase().endsWith(".jar") && hasSignedLibrary(writtenLibraries)) {
+		if (getSource().getName().toLowerCase(Locale.ROOT).endsWith(".jar") && hasSignedLibrary(writtenLibraries)) {
 			writer.writeEntry("META-INF/BOOT.SF", (entryWriter) -> {
 			});
 		}

spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/net/protocol/jar/JarFileUrlKey.java

@@ -18,6 +18,7 @@ package org.springframework.boot.loader.net.protocol.jar;
 
 import java.lang.ref.SoftReference;
 import java.net.URL;
+import java.util.Locale;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 
@@ -54,10 +55,10 @@ final class JarFileUrlKey {
 		String host = url.getHost();
 		int port = (url.getPort() != -1) ? url.getPort() : url.getDefaultPort();
 		String file = url.getFile();
-		value.append(protocol.toLowerCase());
+		value.append(protocol.toLowerCase(Locale.ROOT));
 		value.append(":");
 		if (host != null && !host.isEmpty()) {
-			value.append(host.toLowerCase());
+			value.append(host.toLowerCase(Locale.ROOT));
 			value.append((port != -1) ? ":" + port : "");
 		}
 		value.append((file != null) ? file : "");

spring-boot-project/spring-boot-tools/spring-boot-test-support/src/main/java/org/springframework/boot/testsupport/process/DisabledIfProcessUnavailableCondition.java

@@ -19,6 +19,7 @@ package org.springframework.boot.testsupport.process;
 import java.lang.reflect.AnnotatedElement;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 import java.util.concurrent.TimeUnit;
 import java.util.stream.Stream;
 
@@ -42,7 +43,7 @@ class DisabledIfProcessUnavailableCondition implements ExecutionCondition {
 
 	private static final String USR_LOCAL_BIN = "/usr/local/bin";
 
-	private static final boolean MAC_OS = System.getProperty("os.name").toLowerCase().contains("mac");
+	private static final boolean MAC_OS = System.getProperty("os.name").toLowerCase(Locale.ROOT).contains("mac");
 
 	@Override
 	public ConditionEvaluationResult evaluateExecutionCondition(ExtensionContext context) {