diff --git a/java/src/org/openqa/selenium/Architecture.java b/java/src/org/openqa/selenium/Architecture.java
index a4cfdb7087bee..35798b5ed9475 100644
--- a/java/src/org/openqa/selenium/Architecture.java
+++ b/java/src/org/openqa/selenium/Architecture.java
@@ -17,6 +17,8 @@
 
 package org.openqa.selenium;
 
+import java.util.Locale;
+
 /**
  * Represents the known architectures used in WebDriver. It attempts to smooth over some of Java's
  * rough edges when dealing with microprocessor architectures by, for instance, allowing you to
@@ -98,7 +100,7 @@ public int getDataModel() {
 
   @Override
   public String toString() {
-    return name().toLowerCase();
+    return name().toLowerCase(Locale.ENGLISH);
   }
 
   /**
@@ -121,7 +123,7 @@ public static Architecture getCurrent() {
    */
   public static Architecture extractFromSysProperty(String arch) {
     if (arch != null) {
-      arch = arch.toLowerCase();
+      arch = arch.toLowerCase(Locale.ENGLISH);
     }
 
     // Some architectures are basically the same even though they have different names.  ia32, x86,
diff --git a/java/src/org/openqa/selenium/Platform.java b/java/src/org/openqa/selenium/Platform.java
index 577aaef2881cc..66f7927eaeb9b 100644
--- a/java/src/org/openqa/selenium/Platform.java
+++ b/java/src/org/openqa/selenium/Platform.java
@@ -18,6 +18,7 @@
 package org.openqa.selenium;
 
 import java.util.Arrays;
+import java.util.Locale;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -414,7 +415,7 @@ public static Platform extractFromSysProperty(String osName) {
    * @return the most likely platform based on given operating system name and version
    */
   public static Platform extractFromSysProperty(String osName, String osVersion) {
-    osName = osName.toLowerCase();
+    osName = osName.toLowerCase(Locale.ENGLISH);
     // os.name for android is linux
     if ("dalvik".equalsIgnoreCase(System.getProperty("java.vm.name"))) {
       return Platform.ANDROID;
@@ -434,7 +435,7 @@ public static Platform extractFromSysProperty(String osName, String osVersion) {
         if ("".equals(matcher)) {
           continue;
         }
-        matcher = matcher.toLowerCase();
+        matcher = matcher.toLowerCase(Locale.ENGLISH);
         if (os.isExactMatch(osName, matcher)) {
           return os;
         }
diff --git a/java/src/org/openqa/selenium/Proxy.java b/java/src/org/openqa/selenium/Proxy.java
index ca264597802ae..345256444c4a0 100644
--- a/java/src/org/openqa/selenium/Proxy.java
+++ b/java/src/org/openqa/selenium/Proxy.java
@@ -20,6 +20,7 @@
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
@@ -93,7 +94,8 @@ public Proxy() {
   public Proxy(Map<String, ?> raw) {
     Map<String, Consumer<Object>> setters = new HashMap<>();
     setters.put(
-        PROXY_TYPE, value -> setProxyType(ProxyType.valueOf(((String) value).toUpperCase())));
+        PROXY_TYPE,
+        value -> setProxyType(ProxyType.valueOf(((String) value).toUpperCase(Locale.ENGLISH))));
     setters.put(FTP_PROXY, value -> setFtpProxy((String) value));
     setters.put(HTTP_PROXY, value -> setHttpProxy((String) value));
     setters.put(
@@ -448,7 +450,7 @@ public String toString() {
       case DIRECT:
       case MANUAL:
       case SYSTEM:
-        builder.append(getProxyType().toString().toLowerCase());
+        builder.append(getProxyType().toString().toLowerCase(Locale.ENGLISH));
         break;
 
       case PAC:
diff --git a/java/src/org/openqa/selenium/chrome/ChromeDriverService.java b/java/src/org/openqa/selenium/chrome/ChromeDriverService.java
index 566ceb7717d16..d6beaa0b69489 100644
--- a/java/src/org/openqa/selenium/chrome/ChromeDriverService.java
+++ b/java/src/org/openqa/selenium/chrome/ChromeDriverService.java
@@ -29,6 +29,7 @@
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import org.openqa.selenium.Capabilities;
 import org.openqa.selenium.WebDriverException;
@@ -300,7 +301,7 @@ protected List<String> createArgs() {
       }
 
       if (logLevel != null) {
-        args.add(String.format("--log-level=%s", logLevel.toString().toUpperCase()));
+        args.add(String.format("--log-level=%s", logLevel.toString().toUpperCase(Locale.ENGLISH)));
       }
       if (allowedListIps != null) {
         args.add(String.format("--allowed-ips=%s", allowedListIps));
diff --git a/java/src/org/openqa/selenium/chromium/ChromiumDriverLogLevel.java b/java/src/org/openqa/selenium/chromium/ChromiumDriverLogLevel.java
index 830d4ad01a211..de57b8e917c5c 100644
--- a/java/src/org/openqa/selenium/chromium/ChromiumDriverLogLevel.java
+++ b/java/src/org/openqa/selenium/chromium/ChromiumDriverLogLevel.java
@@ -17,6 +17,7 @@
 
 package org.openqa.selenium.chromium;
 
+import java.util.Locale;
 import java.util.Map;
 import java.util.logging.Level;
 
@@ -46,7 +47,7 @@ public enum ChromiumDriverLogLevel {
 
   @Override
   public String toString() {
-    return super.toString().toLowerCase();
+    return super.toString().toLowerCase(Locale.ENGLISH);
   }
 
   public static ChromiumDriverLogLevel fromString(String text) {
diff --git a/java/src/org/openqa/selenium/devtools/NetworkInterceptor.java b/java/src/org/openqa/selenium/devtools/NetworkInterceptor.java
index d3777136b3780..427e225ac339b 100644
--- a/java/src/org/openqa/selenium/devtools/NetworkInterceptor.java
+++ b/java/src/org/openqa/selenium/devtools/NetworkInterceptor.java
@@ -19,6 +19,7 @@
 
 import static org.openqa.selenium.remote.http.Contents.utf8String;
 
+import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 import org.openqa.selenium.WebDriver;
@@ -105,7 +106,7 @@ public void close() {
   protected HttpMethod convertFromCdpHttpMethod(String method) {
     Require.nonNull("HTTP Method", method);
     try {
-      return HttpMethod.valueOf(method.toUpperCase());
+      return HttpMethod.valueOf(method.toUpperCase(Locale.ENGLISH));
     } catch (IllegalArgumentException e) {
       // Spam in a reasonable value
       return HttpMethod.GET;
diff --git a/java/src/org/openqa/selenium/devtools/idealized/Network.java b/java/src/org/openqa/selenium/devtools/idealized/Network.java
index ec36b5d40d5d0..949811311a6be 100644
--- a/java/src/org/openqa/selenium/devtools/idealized/Network.java
+++ b/java/src/org/openqa/selenium/devtools/idealized/Network.java
@@ -26,6 +26,7 @@
 import java.util.Base64;
 import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 import java.util.concurrent.CancellationException;
@@ -300,7 +301,7 @@ protected Optional<Credentials> getAuthCredentials(URI uri) {
   protected HttpMethod convertFromCdpHttpMethod(String method) {
     Require.nonNull("HTTP Method", method);
     try {
-      return HttpMethod.valueOf(method.toUpperCase());
+      return HttpMethod.valueOf(method.toUpperCase(Locale.ENGLISH));
     } catch (IllegalArgumentException e) {
       // Spam in a reasonable value
       return HttpMethod.GET;
diff --git a/java/src/org/openqa/selenium/edge/EdgeDriverService.java b/java/src/org/openqa/selenium/edge/EdgeDriverService.java
index a089f93055519..0e3c252087882 100644
--- a/java/src/org/openqa/selenium/edge/EdgeDriverService.java
+++ b/java/src/org/openqa/selenium/edge/EdgeDriverService.java
@@ -27,6 +27,7 @@
 import java.time.Duration;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import org.openqa.selenium.Capabilities;
 import org.openqa.selenium.WebDriverException;
@@ -294,7 +295,7 @@ protected List<String> createArgs() {
       }
 
       if (logLevel != null) {
-        args.add(String.format("--log-level=%s", logLevel.toString().toUpperCase()));
+        args.add(String.format("--log-level=%s", logLevel.toString().toUpperCase(Locale.ENGLISH)));
       }
       if (Boolean.TRUE.equals(silent)) {
         args.add("--silent");
diff --git a/java/src/org/openqa/selenium/firefox/FirefoxBinary.java b/java/src/org/openqa/selenium/firefox/FirefoxBinary.java
index 436ebefd0a7b6..8c902c1490b65 100644
--- a/java/src/org/openqa/selenium/firefox/FirefoxBinary.java
+++ b/java/src/org/openqa/selenium/firefox/FirefoxBinary.java
@@ -30,6 +30,7 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 import java.util.stream.Collectors;
@@ -72,7 +73,7 @@ public String toString() {
      * @return the Channel enum value matching the parameter
      */
     public static Channel fromString(String name) {
-      final String lcName = name.toLowerCase();
+      final String lcName = name.toLowerCase(Locale.ENGLISH);
       return stream(Channel.values())
           .filter(ch -> ch.name.equals(lcName))
           .findFirst()
diff --git a/java/src/org/openqa/selenium/firefox/FirefoxDriverLogLevel.java b/java/src/org/openqa/selenium/firefox/FirefoxDriverLogLevel.java
index b3500dc1909c5..b46e762214b84 100644
--- a/java/src/org/openqa/selenium/firefox/FirefoxDriverLogLevel.java
+++ b/java/src/org/openqa/selenium/firefox/FirefoxDriverLogLevel.java
@@ -18,6 +18,7 @@
 package org.openqa.selenium.firefox;
 
 import java.util.Collections;
+import java.util.Locale;
 import java.util.Map;
 import java.util.logging.Level;
 
@@ -47,7 +48,7 @@ public enum FirefoxDriverLogLevel {
 
   @Override
   public String toString() {
-    return super.toString().toLowerCase();
+    return super.toString().toLowerCase(Locale.ENGLISH);
   }
 
   public static FirefoxDriverLogLevel fromString(String text) {
diff --git a/java/src/org/openqa/selenium/grid/config/DescribedOption.java b/java/src/org/openqa/selenium/grid/config/DescribedOption.java
index d11a9e71eb677..3e5aa4e25b133 100644
--- a/java/src/org/openqa/selenium/grid/config/DescribedOption.java
+++ b/java/src/org/openqa/selenium/grid/config/DescribedOption.java
@@ -32,6 +32,7 @@
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Locale;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.ServiceLoader;
@@ -194,7 +195,7 @@ public int hashCode() {
   }
 
   public String getType(Type type) {
-    String className = deriveClass(type).getSimpleName().toLowerCase();
+    String className = deriveClass(type).getSimpleName().toLowerCase(Locale.ENGLISH);
 
     return isCollection(type) ? "list of " + className + "s" : className;
   }
diff --git a/java/src/org/openqa/selenium/grid/distributor/selector/DefaultSlotSelector.java b/java/src/org/openqa/selenium/grid/distributor/selector/DefaultSlotSelector.java
index d10767e4b6c35..37c583a259dc2 100644
--- a/java/src/org/openqa/selenium/grid/distributor/selector/DefaultSlotSelector.java
+++ b/java/src/org/openqa/selenium/grid/distributor/selector/DefaultSlotSelector.java
@@ -21,6 +21,7 @@
 
 import com.google.common.annotations.VisibleForTesting;
 import java.util.Comparator;
+import java.util.Locale;
 import java.util.Set;
 import org.openqa.selenium.Capabilities;
 import org.openqa.selenium.grid.config.Config;
@@ -67,7 +68,7 @@ public Set<SlotId> selectSlot(
   @VisibleForTesting
   long getNumberOfSupportedBrowsers(NodeStatus nodeStatus) {
     return nodeStatus.getSlots().stream()
-        .map(slot -> slot.getStereotype().getBrowserName().toLowerCase())
+        .map(slot -> slot.getStereotype().getBrowserName().toLowerCase(Locale.ENGLISH))
         .distinct()
         .count();
   }
diff --git a/java/src/org/openqa/selenium/grid/node/config/NodeOptions.java b/java/src/org/openqa/selenium/grid/node/config/NodeOptions.java
index ff8fc6d76667a..0a3fd5d82d0ae 100644
--- a/java/src/org/openqa/selenium/grid/node/config/NodeOptions.java
+++ b/java/src/org/openqa/selenium/grid/node/config/NodeOptions.java
@@ -36,6 +36,7 @@
 import java.util.Comparator;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 import java.util.ServiceLoader;
@@ -582,7 +583,9 @@ private void addSpecificDrivers(
 
     Optional<Map.Entry<WebDriverInfo, Collection<SessionFactory>>> first =
         allDrivers.entrySet().stream()
-            .filter(entry -> drivers.contains(entry.getKey().getDisplayName().toLowerCase()))
+            .filter(
+                entry ->
+                    drivers.contains(entry.getKey().getDisplayName().toLowerCase(Locale.ENGLISH)))
             .findFirst();
 
     if (first.isEmpty()) {
@@ -590,8 +593,11 @@ private void addSpecificDrivers(
     }
 
     allDrivers.entrySet().stream()
-        .filter(entry -> drivers.contains(entry.getKey().getDisplayName().toLowerCase()))
-        .sorted(Comparator.comparing(entry -> entry.getKey().getDisplayName().toLowerCase()))
+        .filter(
+            entry -> drivers.contains(entry.getKey().getDisplayName().toLowerCase(Locale.ENGLISH)))
+        .sorted(
+            Comparator.comparing(
+                entry -> entry.getKey().getDisplayName().toLowerCase(Locale.ENGLISH)))
         .peek(this::report)
         .forEach(
             entry -> {
@@ -614,7 +620,8 @@ private Map<WebDriverInfo, Collection<SessionFactory>> discoverDrivers(
       List<WebDriverInfo> driversSM =
           StreamSupport.stream(ServiceLoader.load(WebDriverInfo.class).spliterator(), false)
               .filter(WebDriverInfo::isAvailable)
-              .sorted(Comparator.comparing(info -> info.getDisplayName().toLowerCase()))
+              .sorted(
+                  Comparator.comparing(info -> info.getDisplayName().toLowerCase(Locale.ENGLISH)))
               .collect(Collectors.toList());
       infos.addAll(driversSM);
     } else {
@@ -625,7 +632,8 @@ private Map<WebDriverInfo, Collection<SessionFactory>> discoverDrivers(
       List<WebDriverInfo> localDrivers =
           StreamSupport.stream(ServiceLoader.load(WebDriverInfo.class).spliterator(), false)
               .filter(WebDriverInfo::isPresent)
-              .sorted(Comparator.comparing(info -> info.getDisplayName().toLowerCase()))
+              .sorted(
+                  Comparator.comparing(info -> info.getDisplayName().toLowerCase(Locale.ENGLISH)))
               .collect(Collectors.toList());
       infos.addAll(localDrivers);
     }
@@ -708,7 +716,7 @@ public Optional<WebDriver> createDriver(Capabilities capabilities)
   private int getDriverMaxSessions(WebDriverInfo info, int desiredMaxSessions) {
     // Safari and Safari Technology Preview
     if (info.getMaximumSimultaneousSessions() == 1
-        && SINGLE_SESSION_DRIVERS.contains(info.getDisplayName().toLowerCase())) {
+        && SINGLE_SESSION_DRIVERS.contains(info.getDisplayName().toLowerCase(Locale.ENGLISH))) {
       return info.getMaximumSimultaneousSessions();
     }
     boolean overrideMaxSessions =
diff --git a/java/src/org/openqa/selenium/grid/node/config/SessionCapabilitiesMutator.java b/java/src/org/openqa/selenium/grid/node/config/SessionCapabilitiesMutator.java
index fca93f5035882..79a03e7bcee25 100644
--- a/java/src/org/openqa/selenium/grid/node/config/SessionCapabilitiesMutator.java
+++ b/java/src/org/openqa/selenium/grid/node/config/SessionCapabilitiesMutator.java
@@ -21,6 +21,7 @@
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
 import java.util.function.Function;
@@ -56,7 +57,7 @@ public Capabilities apply(Capabilities capabilities) {
               .setCapability(SE_NO_VNC_PORT, slotStereotype.getCapability(SE_NO_VNC_PORT));
     }
 
-    String browserName = capabilities.getBrowserName().toLowerCase();
+    String browserName = capabilities.getBrowserName().toLowerCase(Locale.ENGLISH);
 
     if ("internet explorer".equalsIgnoreCase(browserName)) {
       return new ImmutableCapabilities(removeUnknownExtensionsForIE(capabilities));
@@ -83,7 +84,7 @@ public Capabilities apply(Capabilities capabilities) {
       Map<String, Object> toReturn = new HashMap<>(slotStereotype.merge(capabilities).asMap());
 
       // Merge browser specific stereotype and capabilities options
-      switch (browserName.toLowerCase()) {
+      switch (browserName.toLowerCase(Locale.ENGLISH)) {
         case "chrome":
         case "microsoftedge":
         case "msedge":
diff --git a/java/src/org/openqa/selenium/grid/node/k8s/OneShotNode.java b/java/src/org/openqa/selenium/grid/node/k8s/OneShotNode.java
index 45887df7da2e2..77cfbb488e1c5 100644
--- a/java/src/org/openqa/selenium/grid/node/k8s/OneShotNode.java
+++ b/java/src/org/openqa/selenium/grid/node/k8s/OneShotNode.java
@@ -30,6 +30,7 @@
 import java.net.URISyntaxException;
 import java.time.Duration;
 import java.time.Instant;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 import java.util.ServiceLoader;
@@ -157,7 +158,7 @@ public static Node create(Config config) {
             .filter(
                 info ->
                     driverName
-                        .map(name -> name.equals(info.getDisplayName().toLowerCase()))
+                        .map(name -> name.equals(info.getDisplayName().toLowerCase(Locale.ENGLISH)))
                         .orElse(true))
             .findFirst()
             .orElseThrow(
diff --git a/java/src/org/openqa/selenium/grid/node/relay/RelayOptions.java b/java/src/org/openqa/selenium/grid/node/relay/RelayOptions.java
index 34d827ce3f2e0..cc98f23489fea 100644
--- a/java/src/org/openqa/selenium/grid/node/relay/RelayOptions.java
+++ b/java/src/org/openqa/selenium/grid/node/relay/RelayOptions.java
@@ -29,6 +29,7 @@
 import java.time.Duration;
 import java.util.Collection;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 import java.util.logging.Logger;
@@ -122,7 +123,7 @@ public String getServiceProtocolVersion() {
 
   private String normalizeProtocolVersion(String protocolVersion) {
     // Support input in the form of "http/1.1" or "HTTP/1.1"
-    return protocolVersion.toUpperCase().replaceAll("/", "_").replaceAll("\\.", "_");
+    return protocolVersion.toUpperCase(Locale.ENGLISH).replaceAll("/", "_").replaceAll("\\.", "_");
   }
 
   // Method being used in SessionSlot
diff --git a/java/src/org/openqa/selenium/grid/web/ResourceHandler.java b/java/src/org/openqa/selenium/grid/web/ResourceHandler.java
index b51f54ce3635b..99474bc78140f 100644
--- a/java/src/org/openqa/selenium/grid/web/ResourceHandler.java
+++ b/java/src/org/openqa/selenium/grid/web/ResourceHandler.java
@@ -42,6 +42,7 @@
 import java.io.UncheckedIOException;
 import java.net.MalformedURLException;
 import java.net.URL;
+import java.util.Locale;
 import java.util.Optional;
 import java.util.stream.Collectors;
 import org.openqa.selenium.internal.Require;
@@ -134,7 +135,7 @@ private String mediaType(String uri) {
     String extension = (index == -1 || uri.length() == index) ? "" : uri.substring(index + 1);
 
     MediaType type;
-    switch (extension.toLowerCase()) {
+    switch (extension.toLowerCase(Locale.ENGLISH)) {
       case "appcache":
         type = CACHE_MANIFEST_UTF_8;
         break;
diff --git a/java/src/org/openqa/selenium/grid/web/ReverseProxyHandler.java b/java/src/org/openqa/selenium/grid/web/ReverseProxyHandler.java
index 7373e1095c2eb..b6a98bb323992 100644
--- a/java/src/org/openqa/selenium/grid/web/ReverseProxyHandler.java
+++ b/java/src/org/openqa/selenium/grid/web/ReverseProxyHandler.java
@@ -23,6 +23,7 @@
 
 import com.google.common.collect.ImmutableSet;
 import java.io.UncheckedIOException;
+import java.util.Locale;
 import java.util.logging.Logger;
 import org.openqa.selenium.internal.Require;
 import org.openqa.selenium.remote.http.HttpClient;
@@ -78,7 +79,7 @@ public HttpResponse execute(HttpRequest req) throws UncheckedIOException {
 
       req.forEachHeader(
           (name, value) -> {
-            if (IGNORED_REQ_HEADERS.contains(name.toLowerCase())) {
+            if (IGNORED_REQ_HEADERS.contains(name.toLowerCase(Locale.ENGLISH))) {
               return;
             }
             toUpstream.addHeader(name, value);
diff --git a/java/src/org/openqa/selenium/io/FileHandler.java b/java/src/org/openqa/selenium/io/FileHandler.java
index b332d8ff78649..8d171649e15e6 100644
--- a/java/src/org/openqa/selenium/io/FileHandler.java
+++ b/java/src/org/openqa/selenium/io/FileHandler.java
@@ -25,6 +25,7 @@
 import java.nio.file.Files;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Locale;
 import java.util.Objects;
 
 /** Utility methods for common filesystem activities */
@@ -41,9 +42,10 @@ public static void copyResource(File outputDir, Class<?> forClassLoader, String.
 
   private static InputStream locateResource(Class<?> forClassLoader, String name)
       throws IOException {
-    String arch = Objects.requireNonNull(System.getProperty("os.arch")).toLowerCase() + "/";
+    String arch =
+        Objects.requireNonNull(System.getProperty("os.arch")).toLowerCase(Locale.ENGLISH) + "/";
     List<String> alternatives = Arrays.asList(name, "/" + name, arch + name, "/" + arch + name);
-    if (System.getProperty("os.name").toLowerCase().contains("mac")) {
+    if (System.getProperty("os.name").toLowerCase(Locale.ENGLISH).contains("mac")) {
       alternatives.add("mac/" + name);
       alternatives.add("/mac/" + name);
     }
diff --git a/java/src/org/openqa/selenium/json/SimplePropertyDescriptor.java b/java/src/org/openqa/selenium/json/SimplePropertyDescriptor.java
index c993a4b73ca98..71247234fbbf8 100644
--- a/java/src/org/openqa/selenium/json/SimplePropertyDescriptor.java
+++ b/java/src/org/openqa/selenium/json/SimplePropertyDescriptor.java
@@ -19,6 +19,7 @@
 
 import java.lang.reflect.Method;
 import java.util.HashMap;
+import java.util.Locale;
 import java.util.Map;
 import java.util.function.Function;
 
@@ -127,7 +128,7 @@ public static SimplePropertyDescriptor[] getPropertyDescriptors(Class<?> clazz)
   }
 
   private static String uncapitalize(String s) {
-    return s.substring(0, 1).toLowerCase() + s.substring(1);
+    return s.substring(0, 1).toLowerCase(Locale.ENGLISH) + s.substring(1);
   }
 
   private static boolean hasPrefix(String prefix, String methodName) {
diff --git a/java/src/org/openqa/selenium/manager/SeleniumManagerOutput.java b/java/src/org/openqa/selenium/manager/SeleniumManagerOutput.java
index 1faee3a809729..3c408679819ba 100644
--- a/java/src/org/openqa/selenium/manager/SeleniumManagerOutput.java
+++ b/java/src/org/openqa/selenium/manager/SeleniumManagerOutput.java
@@ -17,6 +17,7 @@
 package org.openqa.selenium.manager;
 
 import java.util.List;
+import java.util.Locale;
 import java.util.Objects;
 import java.util.logging.Level;
 import org.openqa.selenium.internal.Require;
@@ -75,7 +76,7 @@ private static Log fromJson(JsonInput input) {
       while (input.hasNext()) {
         switch (input.nextName()) {
           case "level":
-            switch (input.nextString().toLowerCase()) {
+            switch (input.nextString().toLowerCase(Locale.ENGLISH)) {
               case "error":
               case "warn":
                 level = Level.WARNING;
diff --git a/java/src/org/openqa/selenium/remote/http/HttpMessage.java b/java/src/org/openqa/selenium/remote/http/HttpMessage.java
index 909d7ecf7bd97..13d7de07205df 100644
--- a/java/src/org/openqa/selenium/remote/http/HttpMessage.java
+++ b/java/src/org/openqa/selenium/remote/http/HttpMessage.java
@@ -28,6 +28,7 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 import java.util.function.BiConsumer;
@@ -91,7 +92,7 @@ public Iterable<String> getHeaderNames() {
    */
   public Iterable<String> getHeaders(String name) {
     return Collections.unmodifiableCollection(
-        headers.getOrDefault(name.toLowerCase(), Collections.emptyList()));
+        headers.getOrDefault(name.toLowerCase(Locale.ENGLISH), Collections.emptyList()));
   }
 
   /**
@@ -101,7 +102,8 @@ public Iterable<String> getHeaders(String name) {
    * @return the value
    */
   public String getHeader(String name) {
-    List<String> values = headers.getOrDefault(name.toLowerCase(), Collections.emptyList());
+    String lcName = name.toLowerCase(Locale.ENGLISH);
+    List<String> values = headers.getOrDefault(lcName, Collections.emptyList());
     return !values.isEmpty() ? values.get(0) : null;
   }
 
@@ -114,7 +116,8 @@ public String getHeader(String name) {
    * @return self
    */
   public M setHeader(String name, String value) {
-    return removeHeader(name.toLowerCase()).addHeader(name.toLowerCase(), value);
+    String lcName = name.toLowerCase(Locale.ENGLISH);
+    return removeHeader(lcName).addHeader(lcName, value);
   }
 
   /**
@@ -126,7 +129,9 @@ public M setHeader(String name, String value) {
    * @return self
    */
   public M addHeader(String name, String value) {
-    headers.computeIfAbsent(name.toLowerCase(), (n) -> new ArrayList<>()).add(value);
+    String lcName = name.toLowerCase(Locale.ENGLISH);
+    List<String> values = headers.computeIfAbsent(lcName, (n) -> new ArrayList<>());
+    values.add(value);
     return self();
   }
 
@@ -137,17 +142,17 @@ public M addHeader(String name, String value) {
    * @return self
    */
   public M removeHeader(String name) {
-    headers.remove(name.toLowerCase());
+    String lcName = name.toLowerCase(Locale.ENGLISH);
+    headers.remove(lcName);
     return self();
   }
 
   public Charset getContentEncoding() {
-    Charset charset = UTF_8;
     try {
       String contentType = getHeader(HttpHeader.ContentType.getName());
       if (contentType != null) {
         return Arrays.stream(contentType.split(";"))
-            .map((e) -> e.trim().toLowerCase())
+            .map((e) -> e.trim().toLowerCase(Locale.ENGLISH))
             .filter((e) -> e.startsWith("charset="))
             .map((e) -> e.substring(e.indexOf('=') + 1))
             .map(Charset::forName)
@@ -157,7 +162,7 @@ public Charset getContentEncoding() {
     } catch (IllegalArgumentException ignored) {
       // Do nothing.
     }
-    return charset;
+    return UTF_8;
   }
 
   @Deprecated
diff --git a/java/src/org/openqa/selenium/remote/http/HttpMethod.java b/java/src/org/openqa/selenium/remote/http/HttpMethod.java
index 73ed0f52aa4b8..fc6622ea40d7f 100644
--- a/java/src/org/openqa/selenium/remote/http/HttpMethod.java
+++ b/java/src/org/openqa/selenium/remote/http/HttpMethod.java
@@ -17,6 +17,8 @@
 
 package org.openqa.selenium.remote.http;
 
+import java.util.Locale;
+
 public enum HttpMethod {
   DELETE,
   GET,
@@ -34,7 +36,7 @@ public static HttpMethod getHttpMethod(String method) {
     }
 
     try {
-      return HttpMethod.valueOf(method.toUpperCase());
+      return HttpMethod.valueOf(method.toUpperCase(Locale.ENGLISH));
     } catch (IllegalArgumentException e) {
       throw new IllegalArgumentException("No enum constant for method: " + method);
     }
diff --git a/java/src/org/openqa/selenium/remote/http/jdk/JdkHttpClient.java b/java/src/org/openqa/selenium/remote/http/jdk/JdkHttpClient.java
index d0b9f76d41e57..6fe1ef7c9a47c 100644
--- a/java/src/org/openqa/selenium/remote/http/jdk/JdkHttpClient.java
+++ b/java/src/org/openqa/selenium/remote/http/jdk/JdkHttpClient.java
@@ -37,6 +37,7 @@
 import java.time.Duration;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 import java.util.Objects;
 import java.util.concurrent.CancellationException;
 import java.util.concurrent.CompletableFuture;
@@ -544,7 +545,7 @@ public List<Proxy> select(URI uri) {
       if (proxy == null) {
         return List.of();
       }
-      if (uri.getScheme().toLowerCase().startsWith("http")) {
+      if (uri.getScheme().toLowerCase(Locale.ENGLISH).startsWith("http")) {
         return List.of(proxy);
       }
       return List.of();
diff --git a/java/src/org/openqa/selenium/remote/http/jdk/JdkHttpMessages.java b/java/src/org/openqa/selenium/remote/http/jdk/JdkHttpMessages.java
index 22d47eda29e19..3491d9c1bbf00 100644
--- a/java/src/org/openqa/selenium/remote/http/jdk/JdkHttpMessages.java
+++ b/java/src/org/openqa/selenium/remote/http/jdk/JdkHttpMessages.java
@@ -24,6 +24,7 @@
 import java.net.http.HttpRequest.BodyPublisher;
 import java.net.http.HttpRequest.BodyPublishers;
 import java.util.List;
+import java.util.Locale;
 import java.util.Objects;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
@@ -94,7 +95,7 @@ public java.net.http.HttpRequest createRequest(HttpRequest req, HttpMethod metho
     req.forEachHeader(
         (name, value) -> {
           // This prevents the IllegalArgumentException that states 'restricted header name: ...'
-          if (IGNORE_HEADERS.contains(name.toLowerCase())) {
+          if (IGNORE_HEADERS.contains(name.toLowerCase(Locale.ENGLISH))) {
             return;
           }
           builder.header(name, value);
diff --git a/java/src/org/openqa/selenium/support/Color.java b/java/src/org/openqa/selenium/support/Color.java
index 0c772ab7cd9b8..bb11a5117741b 100644
--- a/java/src/org/openqa/selenium/support/Color.java
+++ b/java/src/org/openqa/selenium/support/Color.java
@@ -17,6 +17,7 @@
 
 package org.openqa.selenium.support;
 
+import java.util.Locale;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -302,7 +303,7 @@ protected Pattern getPattern() {
   private static class NamedColorConverter extends Converter {
     @Override
     public Color getColor(String value) {
-      return Colors.valueOf(value.toUpperCase()).getColorValue();
+      return Colors.valueOf(value.toUpperCase(Locale.ENGLISH)).getColorValue();
     }
 
     @Override
diff --git a/java/src/org/openqa/selenium/support/events/EventFiringDecorator.java b/java/src/org/openqa/selenium/support/events/EventFiringDecorator.java
index bb02186d91057..25b195b1b5068 100644
--- a/java/src/org/openqa/selenium/support/events/EventFiringDecorator.java
+++ b/java/src/org/openqa/selenium/support/events/EventFiringDecorator.java
@@ -21,6 +21,7 @@
 import java.lang.reflect.Method;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Locale;
 import java.util.Objects;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -301,7 +302,7 @@ private void fireAfterEvents(
 
   private String createEventMethodName(String prefix, String originalMethodName) {
     return prefix
-        + originalMethodName.substring(0, 1).toUpperCase()
+        + originalMethodName.substring(0, 1).toUpperCase(Locale.ENGLISH)
         + originalMethodName.substring(1);
   }
 
diff --git a/java/src/org/openqa/selenium/support/ui/Select.java b/java/src/org/openqa/selenium/support/ui/Select.java
index 5f4021b8b172d..264585e5417f6 100644
--- a/java/src/org/openqa/selenium/support/ui/Select.java
+++ b/java/src/org/openqa/selenium/support/ui/Select.java
@@ -40,7 +40,7 @@ public class Select implements ISelect, WrapsElement {
   public Select(WebElement element) {
     String tagName = element.getTagName();
 
-    if (null == tagName || !"select".equals(tagName.toLowerCase())) {
+    if (!"select".equalsIgnoreCase(tagName)) {
       throw new UnexpectedTagNameException("select", tagName);
     }
 
diff --git a/java/test/org/openqa/selenium/testing/drivers/Browser.java b/java/test/org/openqa/selenium/testing/drivers/Browser.java
index a75d321bd7ac8..3037087237032 100644
--- a/java/test/org/openqa/selenium/testing/drivers/Browser.java
+++ b/java/test/org/openqa/selenium/testing/drivers/Browser.java
@@ -21,6 +21,7 @@
 import static org.openqa.selenium.remote.CapabilityType.UNHANDLED_PROMPT_BEHAVIOUR;
 
 import java.util.HashMap;
+import java.util.Locale;
 import java.util.Map;
 import java.util.logging.Logger;
 import org.openqa.selenium.Capabilities;
@@ -172,7 +173,7 @@ public static Browser detect() {
     }
 
     try {
-      return Browser.valueOf(browserName.toUpperCase());
+      return Browser.valueOf(browserName.toUpperCase(Locale.ENGLISH));
     } catch (IllegalArgumentException e) {
       throw new RuntimeException(
           String.format("Cannot determine driver from name %s", browserName), e);