Cleanup missing use of StandardCharsets (#125424)

Random annoyance that I figured, I'd just fix globally:
We can do a bit of a cleaner job when doing byte <-> string conversion here and there.

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/ConcatFilesTask.java

@@ -8,6 +8,8 @@
  */
 package org.elasticsearch.gradle.internal;
 
+import com.google.common.collect.Iterables;
+
 import org.gradle.api.DefaultTask;
 import org.gradle.api.file.FileCollection;
 import org.gradle.api.tasks.Input;
@@ -85,7 +87,7 @@ public class ConcatFilesTask extends DefaultTask {
     public void concatFiles() throws IOException {
         if (getHeaderLine() != null) {
             getTarget().getParentFile().mkdirs();
-            Files.write(getTarget().toPath(), (getHeaderLine() + '\n').getBytes(StandardCharsets.UTF_8));
+            Files.writeString(getTarget().toPath(), getHeaderLine() + '\n');
         }
 
         // To remove duplicate lines
@@ -95,11 +97,12 @@ public class ConcatFilesTask extends DefaultTask {
                 uniqueLines.addAll(Files.readAllLines(f.toPath(), StandardCharsets.UTF_8));
             }
         }
-        Files.write(getTarget().toPath(), uniqueLines, StandardCharsets.UTF_8, StandardOpenOption.APPEND);
+        Files.write(
-
+            getTarget().toPath(),
-        for (String additionalLine : additionalLines) {
+            Iterables.concat(uniqueLines, additionalLines),
-            Files.write(getTarget().toPath(), (additionalLine + '\n').getBytes(StandardCharsets.UTF_8), StandardOpenOption.APPEND);
+            StandardCharsets.UTF_8,
-        }
+            StandardOpenOption.APPEND
+        );
     }
 
 }

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/DependenciesInfoTask.java

@@ -155,7 +155,7 @@ public class DependenciesInfoTask extends ConventionTask {
             output.append(dep.getGroup() + ":" + dep.getName() + "," + dep.getVersion() + "," + url + "," + licenseType + "\n");
         }
 
-        Files.write(outputFile.toPath(), output.toString().getBytes("UTF-8"), StandardOpenOption.CREATE);
+        Files.writeString(outputFile.toPath(), output.toString(), StandardOpenOption.CREATE);
     }
 
     @Input

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/doc/RestTestsFromDocSnippetTask.java

@@ -24,6 +24,7 @@ import org.gradle.api.tasks.OutputDirectory;
 import java.io.File;
 import java.io.IOException;
 import java.io.PrintWriter;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
@@ -440,7 +441,7 @@ public abstract class RestTestsFromDocSnippetTask extends DocSnippetTask {
             // Now setup the writer
             try {
                 Files.createDirectories(dest.getParent());
-                current = new PrintWriter(dest.toFile(), "UTF-8");
+                current = new PrintWriter(dest.toFile(), StandardCharsets.UTF_8);
                 return current;
             } catch (IOException e) {
                 throw new RuntimeException(e);

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/precommit/FilePermissionsTask.java

@@ -106,7 +106,7 @@ public abstract class FilePermissionsTask extends DefaultTask {
         }
 
         outputMarker.getParentFile().mkdirs();
-        Files.write(outputMarker.toPath(), "done".getBytes("UTF-8"));
+        Files.writeString(outputMarker.toPath(), "done");
     }
 
     @OutputFile

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/precommit/ForbiddenPatternsTask.java

@@ -135,7 +135,7 @@ public abstract class ForbiddenPatternsTask extends DefaultTask {
 
         File outputMarker = getOutputMarker();
         outputMarker.getParentFile().mkdirs();
-        Files.write(outputMarker.toPath(), "done".getBytes(StandardCharsets.UTF_8));
+        Files.writeString(outputMarker.toPath(), "done");
     }
 
     @OutputFile

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/precommit/ThirdPartyAuditTask.java

@@ -364,7 +364,7 @@ public abstract class ThirdPartyAuditTask extends DefaultTask {
         }
         final String forbiddenApisOutput;
         try (ByteArrayOutputStream outputStream = errorOut) {
-            forbiddenApisOutput = outputStream.toString(StandardCharsets.UTF_8.name());
+            forbiddenApisOutput = outputStream.toString(StandardCharsets.UTF_8);
         }
         if (EXPECTED_EXIT_CODES.contains(result.getExitValue()) == false) {
             throw new IllegalStateException("Forbidden APIs cli failed: " + forbiddenApisOutput);
@@ -397,7 +397,7 @@ public abstract class ThirdPartyAuditTask extends DefaultTask {
         }
         final String jdkJarHellCheckList;
         try (ByteArrayOutputStream outputStream = standardOut) {
-            jdkJarHellCheckList = outputStream.toString(StandardCharsets.UTF_8.name());
+            jdkJarHellCheckList = outputStream.toString(StandardCharsets.UTF_8);
         }
         return new TreeSet<>(Arrays.asList(jdkJarHellCheckList.split("\\r?\\n")));
     }

build-tools-internal/src/test/java/org/elasticsearch/gradle/internal/ConcatFilesTaskTests.java

@@ -60,8 +60,8 @@ public class ConcatFilesTaskTests {
         file2.getParentFile().mkdirs();
         file1.createNewFile();
         file2.createNewFile();
-        Files.write(file1.toPath(), ("Hello" + System.lineSeparator() + "Hello").getBytes(StandardCharsets.UTF_8));
+        Files.writeString(file1.toPath(), "Hello" + System.lineSeparator() + "Hello");
-        Files.write(file2.toPath(), ("Hello" + System.lineSeparator() + "नमस्ते").getBytes(StandardCharsets.UTF_8));
+        Files.writeString(file2.toPath(), "Hello" + System.lineSeparator() + "नमस्ते");
 
         concatFilesTask.setFiles(project.fileTree(file1.getParentFile().getParentFile()));
 

build-tools-internal/src/test/java/org/elasticsearch/gradle/internal/precommit/DependencyLicensesTaskTests.java

@@ -244,7 +244,7 @@ public class DependencyLicensesTaskTests {
         Path file = parent.toPath().resolve(name);
         file.toFile().createNewFile();
 
-        Files.write(file, content.getBytes(StandardCharsets.UTF_8));
+        Files.writeString(file, content);
     }
 
     private TaskProvider<DependencyLicensesTask> createDependencyLicensesTask(Project project) {

build-tools-internal/src/test/java/org/elasticsearch/gradle/internal/precommit/FilePermissionsTaskTests.java

@@ -18,7 +18,7 @@ import org.junit.Assert;
 import org.junit.Test;
 
 import java.io.File;
-import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.util.List;
 import java.util.stream.Collectors;
@@ -61,7 +61,7 @@ public class FilePermissionsTaskTests {
         filePermissionsTask.checkInvalidPermissions();
 
         File outputMarker = new File(project.getBuildDir(), "markers/filePermissions");
-        List<String> result = Files.readAllLines(outputMarker.toPath(), Charset.forName("UTF-8"));
+        List<String> result = Files.readAllLines(outputMarker.toPath(), StandardCharsets.UTF_8);
         assertEquals("done", result.get(0));
     }
 
@@ -80,7 +80,7 @@ public class FilePermissionsTaskTests {
         filePermissionsTask.checkInvalidPermissions();
 
         File outputMarker = new File(project.getBuildDir(), "markers/filePermissions");
-        List<String> result = Files.readAllLines(outputMarker.toPath(), Charset.forName("UTF-8"));
+        List<String> result = Files.readAllLines(outputMarker.toPath(), StandardCharsets.UTF_8);
         assertEquals("done", result.get(0));
 
         file.delete();

build-tools/src/main/java/org/elasticsearch/gradle/LoggedExec.java

@@ -38,7 +38,6 @@ import java.io.File;
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.UncheckedIOException;
-import java.io.UnsupportedEncodingException;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.util.List;
@@ -193,11 +192,7 @@ public abstract class LoggedExec extends DefaultTask implements FileSystemOperat
                 execSpec.setWorkingDir(getWorkingDir().get());
             }
             if (getStandardInput().isPresent()) {
-                try {
+                execSpec.setStandardInput(new ByteArrayInputStream(getStandardInput().get().getBytes(StandardCharsets.UTF_8)));
-                    execSpec.setStandardInput(new ByteArrayInputStream(getStandardInput().get().getBytes("UTF-8")));
-                } catch (UnsupportedEncodingException e) {
-                    throw new GradleException("Cannot set standard input", e);
-                }
             }
         });
         int exitValue = execResult.getExitValue();

build-tools/src/main/java/org/elasticsearch/gradle/testclusters/ElasticsearchCluster.java

@@ -42,7 +42,6 @@ import org.gradle.process.ExecOperations;
 import java.io.File;
 import java.io.IOException;
 import java.io.UncheckedIOException;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.security.GeneralSecurityException;
 import java.util.Collection;
@@ -533,7 +532,7 @@ public class ElasticsearchCluster implements TestClusterConfiguration, Named {
         String unicastUris = nodes.stream().flatMap(node -> node.getAllTransportPortURI().stream()).collect(Collectors.joining("\n"));
         nodes.forEach(node -> {
             try {
-                Files.write(node.getConfigDir().resolve("unicast_hosts.txt"), unicastUris.getBytes(StandardCharsets.UTF_8));
+                Files.writeString(node.getConfigDir().resolve("unicast_hosts.txt"), unicastUris);
             } catch (IOException e) {
                 throw new UncheckedIOException("Failed to write unicast_hosts for " + this, e);
             }

distribution/tools/plugin-cli/src/test/java/org/elasticsearch/plugins/cli/InstallPluginActionTests.java

@@ -317,7 +317,7 @@ public class InstallPluginActionTests extends ESTestCase {
             securityPolicyContent.append("\";");
         }
         securityPolicyContent.append("\n};\n");
-        Files.write(pluginDir.resolve("plugin-security.policy"), securityPolicyContent.toString().getBytes(StandardCharsets.UTF_8));
+        Files.writeString(pluginDir.resolve("plugin-security.policy"), securityPolicyContent.toString());
     }
 
     static InstallablePlugin createStablePlugin(String name, Path structure, boolean hasNamedComponentFile, String... additionalProps)
@@ -787,10 +787,10 @@ public class InstallPluginActionTests extends ESTestCase {
     public void testExistingConfig() throws Exception {
         Path envConfigDir = env.v2().configDir().resolve("fake");
         Files.createDirectories(envConfigDir);
-        Files.write(envConfigDir.resolve("custom.yml"), "existing config".getBytes(StandardCharsets.UTF_8));
+        Files.writeString(envConfigDir.resolve("custom.yml"), "existing config");
         Path configDir = pluginDir.resolve("config");
         Files.createDirectory(configDir);
-        Files.write(configDir.resolve("custom.yml"), "new config".getBytes(StandardCharsets.UTF_8));
+        Files.writeString(configDir.resolve("custom.yml"), "new config");
         Files.createFile(configDir.resolve("other.yml"));
         InstallablePlugin pluginZip = createPluginZip("fake", pluginDir);
         installPlugin(pluginZip);
@@ -1033,13 +1033,13 @@ public class InstallPluginActionTests extends ESTestCase {
                     Path shaFile = temp.apply("shas").resolve("downloaded.zip" + shaExtension);
                     byte[] zipbytes = Files.readAllBytes(pluginZipPath);
                     String checksum = shaCalculator.apply(zipbytes);
-                    Files.write(shaFile, checksum.getBytes(StandardCharsets.UTF_8));
+                    Files.writeString(shaFile, checksum);
                     return shaFile.toUri().toURL();
                 } else if ((url + ".asc").equals(urlString)) {
                     final Path ascFile = temp.apply("asc").resolve("downloaded.zip" + ".asc");
                     final byte[] zipBytes = Files.readAllBytes(pluginZipPath);
                     final String asc = signature.apply(zipBytes, secretKey);
-                    Files.write(ascFile, asc.getBytes(StandardCharsets.UTF_8));
+                    Files.writeString(ascFile, asc);
                     return ascFile.toUri().toURL();
                 }
                 return null;

libs/entitlement/qa/entitlement-test-plugin/src/main/java/org/elasticsearch/entitlement/qa/test/NioFilesActions.java

@@ -426,7 +426,7 @@ class NioFilesActions {
     @EntitlementTest(expectedAccess = PLUGINS)
     static void checkFilesWrite() throws IOException {
         var directory = EntitledActions.createTempDirectoryForWrite();
-        Files.write(directory.resolve("file"), "foo".getBytes(StandardCharsets.UTF_8));
+        Files.writeString(directory.resolve("file"), "foo");
     }
 
     @EntitlementTest(expectedAccess = PLUGINS)

modules/ingest-common/src/test/java/org/elasticsearch/ingest/common/URLDecodeProcessorTests.java

@@ -48,7 +48,7 @@ public class URLDecodeProcessorTests extends AbstractStringProcessorTestCase<Str
 
     private static boolean isValidUrlEncodedString(String s) {
         try {
-            URLDecoder.decode(s, "UTF-8");
+            URLDecoder.decode(s, StandardCharsets.UTF_8);
             return true;
         } catch (Exception e) {
             return false;

modules/lang-mustache/src/test/java/org/elasticsearch/script/mustache/MustacheTests.java

@@ -425,7 +425,7 @@ public class MustacheTests extends ESTestCase {
         assertScript(
             "{{#url}}prefix_{{s}}{{/url}}",
             singletonMap("s", random),
-            equalTo("prefix_" + URLEncoder.encode(random, StandardCharsets.UTF_8.name()))
+            equalTo("prefix_" + URLEncoder.encode(random, StandardCharsets.UTF_8))
         );
     }
 

modules/lang-painless/src/doc/java/org/elasticsearch/painless/ContextApiSpecGenerator.java

@@ -46,7 +46,7 @@ public class ContextApiSpecGenerator {
             PrintStream jsonStream = new PrintStream(
                 Files.newOutputStream(json, StandardOpenOption.CREATE_NEW, StandardOpenOption.WRITE),
                 false,
-                StandardCharsets.UTF_8.name()
+                StandardCharsets.UTF_8
             )
         ) {
 
@@ -63,7 +63,7 @@ public class ContextApiSpecGenerator {
                 PrintStream jsonStream = new PrintStream(
                     Files.newOutputStream(json, StandardOpenOption.CREATE_NEW, StandardOpenOption.WRITE),
                     false,
-                    StandardCharsets.UTF_8.name()
+                    StandardCharsets.UTF_8
                 )
             ) {
 

modules/transport-netty4/src/test/java/org/elasticsearch/http/netty4/Netty4HttpServerTransportTests.java

@@ -95,7 +95,6 @@ import org.junit.Before;
 
 import java.io.IOException;
 import java.net.InetSocketAddress;
-import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -351,14 +350,14 @@ public class Netty4HttpServerTransportTests extends AbstractHttpServerTransportT
             final TransportAddress remoteAddress = randomFrom(transport.boundAddress().boundAddresses());
 
             try (Netty4HttpClient client = new Netty4HttpClient()) {
-                final String url = "/" + new String(new byte[maxInitialLineLength], Charset.forName("UTF-8"));
+                final String url = "/" + new String(new byte[maxInitialLineLength], StandardCharsets.UTF_8);
                 final FullHttpRequest request = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET, url);
 
                 final FullHttpResponse response = client.send(remoteAddress.address(), request);
                 try {
                     assertThat(response.status(), equalTo(HttpResponseStatus.BAD_REQUEST));
                     assertThat(
-                        new String(response.content().array(), Charset.forName("UTF-8")),
+                        new String(response.content().array(), StandardCharsets.UTF_8),
                         containsString("you sent a bad request and you should feel bad")
                     );
                 } finally {

plugins/analysis-icu/src/main/java/org/elasticsearch/plugin/analysis/icu/IcuCollationTokenFilterFactory.java

@@ -21,7 +21,7 @@ import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.analysis.AbstractTokenFilterFactory;
 
 import java.io.IOException;
-import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.InvalidPathException;
 
@@ -51,7 +51,7 @@ public class IcuCollationTokenFilterFactory extends AbstractTokenFilterFactory {
         if (rules != null) {
             Exception failureToResolve = null;
             try {
-                rules = Streams.copyToString(Files.newBufferedReader(environment.configDir().resolve(rules), Charset.forName("UTF-8")));
+                rules = Streams.copyToString(Files.newBufferedReader(environment.configDir().resolve(rules), StandardCharsets.UTF_8));
             } catch (IOException | SecurityException | InvalidPathException e) {
                 failureToResolve = e;
             }

plugins/mapper-annotated-text/src/test/java/org/elasticsearch/index/mapper/annotatedtext/AnnotatedTextHighlighterTests.java

@@ -45,6 +45,7 @@ import org.elasticsearch.search.fetch.subphase.highlight.LimitTokenOffsetAnalyze
 import org.elasticsearch.test.ESTestCase;
 
 import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
 import java.text.BreakIterator;
 import java.util.ArrayList;
 import java.util.Locale;
@@ -167,7 +168,7 @@ public class AnnotatedTextHighlighterTests extends ESTestCase {
         // on marked-up
         // content using an "annotated_text" type field.
         String url = "https://en.wikipedia.org/wiki/Key_Word_in_Context";
-        String encodedUrl = URLEncoder.encode(url, "UTF-8");
+        String encodedUrl = URLEncoder.encode(url, StandardCharsets.UTF_8);
         String annotatedWord = "[highlighting](" + encodedUrl + ")";
         String highlightedAnnotatedWord = "[highlighting]("
             + AnnotatedPassageFormatter.SEARCH_HIT_TYPE

qa/no-bootstrap-tests/src/test/java/org/elasticsearch/bootstrap/SpawnerNoBootstrapTests.java

@@ -27,7 +27,6 @@ import org.elasticsearch.test.GraalVMThreadsFilter;
 import org.elasticsearch.test.MockLog;
 
 import java.io.IOException;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.attribute.PosixFileAttributeView;
@@ -270,7 +269,7 @@ public class SpawnerNoBootstrapTests extends LuceneTestCase {
     private void createControllerProgram(final Path outputFile) throws IOException {
         final Path outputDir = outputFile.getParent();
         Files.createDirectories(outputDir);
-        Files.write(outputFile, CONTROLLER_SOURCE.getBytes(StandardCharsets.UTF_8));
+        Files.writeString(outputFile, CONTROLLER_SOURCE);
         final PosixFileAttributeView view = Files.getFileAttributeView(outputFile, PosixFileAttributeView.class);
         if (view != null) {
             final Set<PosixFilePermission> perms = new HashSet<>();

qa/packaging/src/test/java/org/elasticsearch/packaging/util/FileUtils.java

@@ -208,7 +208,7 @@ public class FileUtils {
     public static String slurpAllLogs(Path logPath, String activeLogFile, String rotatedLogFilesGlob) {
         StringJoiner logFileJoiner = new StringJoiner("\n");
         try {
-            logFileJoiner.add(new String(Files.readAllBytes(logPath.resolve(activeLogFile)), StandardCharsets.UTF_8));
+            logFileJoiner.add(Files.readString(logPath.resolve(activeLogFile)));
 
             for (Path rotatedLogFile : FileUtils.lsGlob(logPath, rotatedLogFilesGlob)) {
                 logFileJoiner.add(FileUtils.slurpTxtorGz(rotatedLogFile));

server/src/internalClusterTest/java/org/elasticsearch/index/store/CorruptedFileIT.java

@@ -217,7 +217,7 @@ public class CorruptedFileIT extends ESIntegTestCase {
                             return;
                         }
                         BytesStreamOutput os = new BytesStreamOutput();
-                        PrintStream out = new PrintStream(os, false, StandardCharsets.UTF_8.name());
+                        PrintStream out = new PrintStream(os, false, StandardCharsets.UTF_8);
                         CheckIndex.Status status = store.checkIndex(out);
                         out.flush();
                         if (status.clean == false) {

server/src/internalClusterTest/java/org/elasticsearch/ingest/IngestFileSettingsIT.java

@@ -129,7 +129,7 @@ public class IngestFileSettingsIT extends ESIntegTestCase {
 
         logger.info("--> writing JSON config to node {} with path {}", node, tempFilePath);
         logger.info(Strings.format(json, version));
-        Files.write(tempFilePath, Strings.format(json, version).getBytes(StandardCharsets.UTF_8));
+        Files.writeString(tempFilePath, Strings.format(json, version));
         Files.move(tempFilePath, fileSettingsService.watchedFile(), StandardCopyOption.ATOMIC_MOVE);
     }
 

server/src/internalClusterTest/java/org/elasticsearch/readiness/ReadinessClusterIT.java

@@ -29,7 +29,6 @@ import org.elasticsearch.test.InternalTestCluster;
 import org.junit.Before;
 
 import java.io.IOException;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
@@ -252,7 +251,7 @@ public class ReadinessClusterIT extends ESIntegTestCase {
         Path fileSettings = configDir.resolve("operator").resolve("settings.json");
         Files.createDirectories(fileSettings.getParent());
 
-        Files.write(tempFilePath, Strings.format(json, version).getBytes(StandardCharsets.UTF_8));
+        Files.writeString(tempFilePath, Strings.format(json, version));
         Files.move(tempFilePath, fileSettings, StandardCopyOption.ATOMIC_MOVE);
         logger.info("--> New file settings: [{}]", Strings.format(json, version));
     }

server/src/internalClusterTest/java/org/elasticsearch/search/aggregations/metrics/ScriptedMetricIT.java

@@ -332,13 +332,10 @@ public class ScriptedMetricIT extends ESIntegTestCase {
             // When using the MockScriptPlugin we can map File scripts to inline scripts:
             // the name of the file script is used in test method while the source of the file script
             // must match a predefined script from CustomScriptPlugin.pluginScripts() method
-            Files.write(scripts.resolve("init_script.mockscript"), "vars.multiplier = 3".getBytes("UTF-8"));
+            Files.writeString(scripts.resolve("init_script.mockscript"), "vars.multiplier = 3");
-            Files.write(scripts.resolve("map_script.mockscript"), "state.list.add(vars.multiplier)".getBytes("UTF-8"));
+            Files.writeString(scripts.resolve("map_script.mockscript"), "state.list.add(vars.multiplier)");
-            Files.write(scripts.resolve("combine_script.mockscript"), "sum state values as a new aggregation".getBytes("UTF-8"));
+            Files.writeString(scripts.resolve("combine_script.mockscript"), "sum state values as a new aggregation");
-            Files.write(
+            Files.writeString(scripts.resolve("reduce_script.mockscript"), "sum all states (lists) values as a new aggregation");
-                scripts.resolve("reduce_script.mockscript"),
-                "sum all states (lists) values as a new aggregation".getBytes("UTF-8")
-            );
         } catch (IOException e) {
             throw new RuntimeException("failed to create scripts");
         }

server/src/internalClusterTest/java/org/elasticsearch/search/fields/SearchFieldsIT.java

@@ -37,6 +37,7 @@ import org.elasticsearch.xcontent.XContentBuilder;
 import org.elasticsearch.xcontent.XContentFactory;
 import org.elasticsearch.xcontent.XContentType;
 
+import java.nio.charset.StandardCharsets;
 import java.time.Instant;
 import java.time.ZoneOffset;
 import java.time.ZonedDateTime;
@@ -612,7 +613,7 @@ public class SearchFieldsIT extends ESIntegTestCase {
                     .field("double_field", 6.0d)
                     .field("date_field", DateFormatter.forPattern("date_optional_time").format(date))
                     .field("boolean_field", true)
-                    .field("binary_field", Base64.getEncoder().encodeToString("testing text".getBytes("UTF-8")))
+                    .field("binary_field", Base64.getEncoder().encodeToString("testing text".getBytes(StandardCharsets.UTF_8)))
                     .endObject()
             )
             .get();
@@ -661,7 +662,10 @@ public class SearchFieldsIT extends ESIntegTestCase {
                 String dateTime = DateFormatter.forPattern("date_optional_time").format(date);
                 assertThat(searchHit.getFields().get("date_field").getValue(), equalTo((Object) dateTime));
                 assertThat(searchHit.getFields().get("boolean_field").getValue(), equalTo((Object) Boolean.TRUE));
-                assertThat(searchHit.getFields().get("binary_field").getValue(), equalTo(new BytesArray("testing text".getBytes("UTF8"))));
+                assertThat(
+                    searchHit.getFields().get("binary_field").getValue(),
+                    equalTo(new BytesArray("testing text".getBytes(StandardCharsets.UTF_8)))
+                );
             }
         );
     }

server/src/main/java/org/elasticsearch/index/shard/IndexShard.java

@@ -3280,7 +3280,7 @@ public class IndexShard extends AbstractIndexShardComponent implements IndicesCl
         } else {
             // full checkindex
             final BytesStreamOutput os = new BytesStreamOutput();
-            final PrintStream out = new PrintStream(os, false, StandardCharsets.UTF_8.name());
+            final PrintStream out = new PrintStream(os, false, StandardCharsets.UTF_8);
             final CheckIndex.Status status = store.checkIndex(out);
             out.flush();
             if (status.clean == false) {

server/src/main/java/org/elasticsearch/node/Node.java

@@ -92,7 +92,7 @@ import java.io.File;
 import java.io.IOException;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
-import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
@@ -653,7 +653,7 @@ public class Node implements Closeable {
      */
     private void writePortsFile(String type, BoundTransportAddress boundAddress) {
         Path tmpPortsFile = environment.logsDir().resolve(type + ".ports.tmp");
-        try (BufferedWriter writer = Files.newBufferedWriter(tmpPortsFile, Charset.forName("UTF-8"))) {
+        try (BufferedWriter writer = Files.newBufferedWriter(tmpPortsFile, StandardCharsets.UTF_8)) {
             for (TransportAddress address : boundAddress.boundAddresses()) {
                 InetAddress inetAddress = InetAddress.getByName(address.getAddress());
                 writer.write(NetworkAddress.format(new InetSocketAddress(inetAddress, address.getPort())) + "\n");

server/src/test/java/org/elasticsearch/common/ChannelsTests.java

@@ -25,6 +25,7 @@ import java.nio.channels.FileChannel;
 import java.nio.channels.FileLock;
 import java.nio.channels.ReadableByteChannel;
 import java.nio.channels.WritableByteChannel;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
 
@@ -42,7 +43,7 @@ public class ChannelsTests extends ESTestCase {
         Path tmpFile = createTempFile();
         FileChannel randomAccessFile = FileChannel.open(tmpFile, StandardOpenOption.READ, StandardOpenOption.WRITE);
         fileChannel = new MockFileChannel(randomAccessFile);
-        randomBytes = randomUnicodeOfLength(scaledRandomIntBetween(10, 100000)).getBytes("UTF-8");
+        randomBytes = randomUnicodeOfLength(scaledRandomIntBetween(10, 100000)).getBytes(StandardCharsets.UTF_8);
     }
 
     @Override

server/src/test/java/org/elasticsearch/common/compress/DeflateCompressedXContentTests.java

@@ -20,6 +20,7 @@ import org.junit.Assert;
 
 import java.io.IOException;
 import java.io.OutputStream;
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.Random;
 
@@ -61,7 +62,7 @@ public class DeflateCompressedXContentTests extends ESTestCase {
     }
 
     public void testDifferentCompressedRepresentation() throws Exception {
-        byte[] b = "---\nf:abcdefghijabcdefghij".getBytes("UTF-8");
+        byte[] b = "---\nf:abcdefghijabcdefghij".getBytes(StandardCharsets.UTF_8);
         BytesStreamOutput bout = new BytesStreamOutput();
         try (OutputStream out = compressor.threadLocalOutputStream(bout)) {
             out.write(b);

server/src/test/java/org/elasticsearch/common/settings/LocallyMountedSecretsTests.java

@@ -236,7 +236,7 @@ public class LocallyMountedSecretsTests extends ESTestCase {
     private void writeTestFile(Path path, String contents) throws IOException {
         Path tempFilePath = createTempFile();
 
-        Files.write(tempFilePath, contents.getBytes(StandardCharsets.UTF_8));
+        Files.writeString(tempFilePath, contents);
         Files.createDirectories(path.getParent());
         Files.move(tempFilePath, path, StandardCopyOption.ATOMIC_MOVE);
     }

server/src/test/java/org/elasticsearch/common/xcontent/BaseXContentTestCase.java

@@ -43,6 +43,7 @@ import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.math.BigDecimal;
 import java.math.BigInteger;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Path;
 import java.time.DayOfWeek;
 import java.time.Duration;
@@ -1192,7 +1193,7 @@ public abstract class BaseXContentTestCase extends ESTestCase {
     }
 
     private static byte[] randomBytes() throws Exception {
-        return randomUnicodeOfLength(scaledRandomIntBetween(10, 1000)).getBytes("UTF-8");
+        return randomUnicodeOfLength(scaledRandomIntBetween(10, 1000)).getBytes(StandardCharsets.UTF_8);
     }
 
     @FunctionalInterface

server/src/test/java/org/elasticsearch/common/xcontent/XContentParserUtilsTests.java

@@ -92,7 +92,7 @@ public class XContentParserUtilsTests extends ESTestCase {
     }
 
     public void testStoredFieldsValueBinary() throws IOException {
-        final byte[] value = randomUnicodeOfLength(scaledRandomIntBetween(10, 1000)).getBytes("UTF-8");
+        final byte[] value = randomUnicodeOfLength(scaledRandomIntBetween(10, 1000)).getBytes(StandardCharsets.UTF_8);
         assertParseFieldsSimpleValue(value, (xcontentType, result) -> {
             if (xcontentType.canonical() == XContentType.JSON) {
                 // binary values will be parsed back and returned as base64 strings when reading from json

server/src/test/java/org/elasticsearch/common/xcontent/builder/XContentBuilderTests.java

@@ -167,7 +167,7 @@ public class XContentBuilderTests extends ESTestCase {
         gen.writeStartObject();
         gen.writeStringField("name", "something");
         gen.flush();
-        bos.write(", source : { test : \"value\" }".getBytes("UTF8"));
+        bos.write(", source : { test : \"value\" }".getBytes(StandardCharsets.UTF_8));
         gen.writeStringField("name2", "something2");
         gen.writeEndObject();
         gen.close();

server/src/test/java/org/elasticsearch/index/mapper/NumberFieldTypeTests.java

@@ -848,7 +848,7 @@ public class NumberFieldTypeTests extends FieldTypeTestCase {
 
         public void write(XContentBuilder b) throws IOException {
             if (value instanceof BigInteger) {
-                b.rawField("field", new ByteArrayInputStream(value.toString().getBytes("UTF-8")), XContentType.JSON);
+                b.rawField("field", new ByteArrayInputStream(value.toString().getBytes(StandardCharsets.UTF_8)), XContentType.JSON);
             } else {
                 b.field("field", value);
             }

test/fixtures/krb5kdc-fixture/src/main/java/org/elasticsearch/test/fixtures/krb5kdc/Krb5kDcContainer.java

@@ -158,7 +158,7 @@ public final class Krb5kDcContainer extends DockerEnvironmentAwareTestContainer
         }
         try {
             krb5ConfFile = temporaryFolder.newFile("krb5.conf").toPath();
-            Files.write(krb5ConfFile, getConf().getBytes(StandardCharsets.UTF_8));
+            Files.writeString(krb5ConfFile, getConf());
             return krb5ConfFile;
         } catch (IOException e) {
             throw new RuntimeException(e);

test/fixtures/old-elasticsearch/src/main/java/oldes/OldElasticsearch.java

@@ -128,11 +128,11 @@ public class OldElasticsearch {
         }
 
         Path tmp = Files.createTempFile(baseDir, null, null);
-        Files.write(tmp, Integer.toString(port).getBytes(StandardCharsets.UTF_8));
+        Files.writeString(tmp, Integer.toString(port));
         Files.move(tmp, baseDir.resolve("ports"), StandardCopyOption.ATOMIC_MOVE);
 
         tmp = Files.createTempFile(baseDir, null, null);
-        Files.write(tmp, Integer.toString(pid).getBytes(StandardCharsets.UTF_8));
+        Files.writeString(tmp, Integer.toString(pid));
         Files.move(tmp, baseDir.resolve("pid"), StandardCopyOption.ATOMIC_MOVE);
     }
 }

test/framework/src/main/java/org/elasticsearch/index/mapper/NumberTypeOutOfRangeSpec.java

@@ -15,6 +15,7 @@ import org.elasticsearch.xcontent.XContentType;
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.math.BigInteger;
+import java.nio.charset.StandardCharsets;
 
 public class NumberTypeOutOfRangeSpec {
 
@@ -34,7 +35,7 @@ public class NumberTypeOutOfRangeSpec {
 
     public void write(XContentBuilder b) throws IOException {
         if (value instanceof BigInteger) {
-            b.rawField("field", new ByteArrayInputStream(value.toString().getBytes("UTF-8")), XContentType.JSON);
+            b.rawField("field", new ByteArrayInputStream(value.toString().getBytes(StandardCharsets.UTF_8)), XContentType.JSON);
         } else {
             b.field("field", value);
         }

test/framework/src/main/java/org/elasticsearch/test/store/MockFSDirectoryFactory.java

@@ -83,7 +83,7 @@ public class MockFSDirectoryFactory implements IndexStorePlugin.DirectoryFactory
                 }
                 try {
                     BytesStreamOutput os = new BytesStreamOutput();
-                    PrintStream out = new PrintStream(os, false, StandardCharsets.UTF_8.name());
+                    PrintStream out = new PrintStream(os, false, StandardCharsets.UTF_8);
                     CheckIndex.Status status = store.checkIndex(out);
                     out.flush();
                     if (status.clean == false) {

x-pack/license-tools/src/test/java/org/elasticsearch/license/licensor/tools/LicenseGenerationToolTests.java

@@ -81,7 +81,7 @@ public class LicenseGenerationToolTests extends CommandTestCase {
         TestUtils.LicenseSpec inputLicenseSpec = TestUtils.generateRandomLicenseSpec(License.VERSION_CURRENT);
         String licenseSpecString = TestUtils.generateLicenseSpecString(inputLicenseSpec);
         Path licenseSpecFile = createTempFile();
-        Files.write(licenseSpecFile, licenseSpecString.getBytes(StandardCharsets.UTF_8));
+        Files.writeString(licenseSpecFile, licenseSpecString);
         String output = execute(
             "--publicKeyPath",
             pubKeyPath.toString(),

x-pack/license-tools/src/test/java/org/elasticsearch/license/licensor/tools/LicenseVerificationToolTests.java

@@ -15,7 +15,6 @@ import org.elasticsearch.license.License;
 import org.elasticsearch.license.licensor.TestUtils;
 import org.junit.Before;
 
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 
@@ -74,7 +73,7 @@ public class LicenseVerificationToolTests extends CommandTestCase {
         final TimeValue oneHour = TimeValue.timeValueHours(1);
         License signedLicense = TestUtils.generateSignedLicense(oneHour, pubKeyPath, priKeyPath);
         Path licenseSpecFile = createTempFile();
-        Files.write(licenseSpecFile, TestUtils.dumpLicense(signedLicense).getBytes(StandardCharsets.UTF_8));
+        Files.writeString(licenseSpecFile, TestUtils.dumpLicense(signedLicense));
         String output = execute("--publicKeyPath", pubKeyPath.toString(), "--licenseFile", licenseSpecFile.toString());
         assertFalse(output, output.isEmpty());
     }

x-pack/plugin/autoscaling/src/internalClusterTest/java/org/elasticsearch/xpack/autoscaling/AutoscalingFileSettingsIT.java

@@ -103,7 +103,7 @@ public class AutoscalingFileSettingsIT extends AutoscalingIntegTestCase {
         Path tempFilePath = createTempFile();
 
         logger.info("--> writing JSON config to node {} with path {}", node, tempFilePath);
-        Files.write(tempFilePath, Strings.format(json, version).getBytes(StandardCharsets.UTF_8));
+        Files.writeString(tempFilePath, Strings.format(json, version));
         Files.move(tempFilePath, fileSettingsService.watchedFile(), StandardCopyOption.ATOMIC_MOVE);
     }
 

x-pack/plugin/ml/qa/no-bootstrap-tests/src/test/java/org/elasticsearch/xpack/ml/utils/NamedPipeHelperNoBootstrapTests.java

@@ -192,7 +192,7 @@ public class NamedPipeHelperNoBootstrapTests extends LuceneTestCase {
     }
 
     private static void writeLineToPipeUnix(String pipeName, String line) throws IOException {
-        Files.write(PathUtils.get(pipeName), (line + '\n').getBytes(StandardCharsets.UTF_8), StandardOpenOption.WRITE);
+        Files.writeString(PathUtils.get(pipeName), line + '\n', StandardOpenOption.WRITE);
     }
 
     private static void writeLineToPipeWindows(String pipeName, Pointer handle, String line) throws IOException {

x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/datafeed/extractor/aggregation/AggregationToJsonProcessorTests.java

@@ -701,7 +701,7 @@ public class AggregationToJsonProcessorTests extends ESTestCase {
         processor.process(aggregations);
         processor.writeAllDocsCancellable(_timestamp -> false, outputStream);
         keyValuePairsWritten = processor.getKeyValueCount();
-        return outputStream.toString(StandardCharsets.UTF_8.name());
+        return outputStream.toString(StandardCharsets.UTF_8);
     }
 
     private String aggToStringComposite(Set<String> fields, List<InternalComposite.InternalBucket> buckets) throws IOException {

x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/datafeed/extractor/scroll/SearchHitToJsonProcessorTests.java

@@ -79,6 +79,6 @@ public class SearchHitToJsonProcessorTests extends ESTestCase {
                 hitProcessor.process(searchHits[i], new SourceSupplier(searchHits[i]));
             }
         }
-        return outputStream.toString(StandardCharsets.UTF_8.name());
+        return outputStream.toString(StandardCharsets.UTF_8);
     }
 }

x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/job/persistence/StateStreamerTests.java

@@ -80,7 +80,7 @@ public class StateStreamerTests extends ESTestCase {
         StateStreamer stateStreamer = new StateStreamer(clientBuilder.build());
         stateStreamer.restoreStateToStream(JOB_ID, modelSnapshot, stream);
 
-        String[] restoreData = stream.toString(StandardCharsets.UTF_8.name()).split("\0");
+        String[] restoreData = stream.toString(StandardCharsets.UTF_8).split("\0");
         assertEquals(3, restoreData.length);
         assertEquals("{\"modName1\":\"modVal1\"}", restoreData[0]);
         assertEquals("{\"modName2\":\"modVal2\"}", restoreData[1]);

x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/process/NativeControllerTests.java

@@ -77,7 +77,7 @@ public class NativeControllerTests extends ESTestCase {
 
         assertEquals(
             "1\tstart\tmy_process\t--arg1\t--arg2=42\t--arg3=something with spaces\n",
-            commandStream.toString(StandardCharsets.UTF_8.name())
+            commandStream.toString(StandardCharsets.UTF_8)
         );
 
         mockNativeProcessLoggingStreamEnds.countDown();
@@ -115,7 +115,7 @@ public class NativeControllerTests extends ESTestCase {
 
         assertEquals(
             "1\tstart\tmy_process\t--arg1\t--arg2=666\t--arg3=something different with spaces\n",
-            commandStream.toString(StandardCharsets.UTF_8.name())
+            commandStream.toString(StandardCharsets.UTF_8)
         );
         assertEquals("ML controller failed to execute command [1]: [some problem]", e.getMessage());
 

x-pack/plugin/monitoring/src/internalClusterTest/java/org/elasticsearch/xpack/monitoring/integration/MonitoringIT.java

@@ -52,6 +52,7 @@ import java.lang.management.LockInfo;
 import java.lang.management.ManagementFactory;
 import java.lang.management.MonitorInfo;
 import java.lang.management.ThreadInfo;
+import java.nio.charset.StandardCharsets;
 import java.time.Instant;
 import java.time.ZoneOffset;
 import java.util.Arrays;
@@ -130,7 +131,7 @@ public class MonitoringIT extends ESSingleNodeTestCase {
 
             final MonitoringBulkResponse bulkResponse = new MonitoringBulkRequestBuilder(client()).add(
                 system,
-                new BytesArray(createBulkEntity().getBytes("UTF-8")),
+                new BytesArray(createBulkEntity().getBytes(StandardCharsets.UTF_8)),
                 XContentType.JSON,
                 System.currentTimeMillis(),
                 interval.millis()

x-pack/plugin/security/src/test/java/org/elasticsearch/xpack/security/authc/file/FileUserRolesStoreTests.java

@@ -280,7 +280,7 @@ public class FileUserRolesStoreTests extends ESTestCase {
 
     private Path writeUsersRoles(String input) throws Exception {
         Path file = getUsersRolesPath();
-        Files.write(file, input.getBytes(StandardCharsets.UTF_8));
+        Files.writeString(file, input);
         return file;
     }
 
@@ -292,7 +292,7 @@ public class FileUserRolesStoreTests extends ESTestCase {
 
     private void assertInvalidInputIsSilentlyIgnored(String input) throws Exception {
         Path file = createTempFile();
-        Files.write(file, input.getBytes(StandardCharsets.UTF_8));
+        Files.writeString(file, input);
         Map<String, String[]> usersRoles = FileUserRolesStore.parseFile(file, null);
         String reason = Strings.format("Expected userRoles to be empty, but was %s", usersRoles.keySet());
         assertThat(reason, usersRoles.keySet(), hasSize(0));

x-pack/plugin/security/src/test/java/org/elasticsearch/xpack/security/authc/saml/SamlRealmTests.java

@@ -59,7 +59,6 @@ import org.opensaml.security.x509.X509Credential;
 
 import java.io.IOException;
 import java.io.OutputStream;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.security.GeneralSecurityException;
@@ -145,7 +144,7 @@ public class SamlRealmTests extends SamlTestCase {
 
     public void testReadIdpMetadataFromHttps() throws Exception {
         final Path path = getDataPath("idp1.xml");
-        final String body = new String(Files.readAllBytes(path), StandardCharsets.UTF_8);
+        final String body = Files.readString(path);
         TestsSSLService sslService = buildTestSslService();
         try (MockWebServer proxyServer = new MockWebServer(sslService.sslContext("xpack.security.http.ssl"), false)) {
             proxyServer.start();
@@ -204,7 +203,7 @@ public class SamlRealmTests extends SamlTestCase {
 
     public void testRetryFailedHttpsMetadata() throws Exception {
         final Path path = getDataPath("idp1.xml");
-        final String body = new String(Files.readAllBytes(path), StandardCharsets.UTF_8);
+        final String body = Files.readString(path);
         TestsSSLService sslService = buildTestSslService();
         doTestReloadFailedHttpsMetadata(body, sslService, true);
         doTestReloadFailedHttpsMetadata(body, sslService, false);

x-pack/plugin/security/src/test/java/org/elasticsearch/xpack/security/operator/FileOperatorUsersStoreTests.java

@@ -491,7 +491,7 @@ public class FileOperatorUsersStoreTests extends ESTestCase {
 
     private Path writeOperatorUsers(String input) throws IOException {
         Path file = getOperatorUsersPath();
-        Files.write(file, input.getBytes(StandardCharsets.UTF_8));
+        Files.writeString(file, input);
         return file;
     }
 

x-pack/plugin/slm/src/internalClusterTest/java/org/elasticsearch/xpack/slm/SLMFileSettingsIT.java

@@ -164,7 +164,7 @@ public class SLMFileSettingsIT extends AbstractSnapshotIntegTestCase {
         Files.createDirectories(fileSettingsService.watchedFileDir());
         Path tempFilePath = createTempFile();
 
-        Files.write(tempFilePath, Strings.format(json, version).getBytes(StandardCharsets.UTF_8));
+        Files.writeString(tempFilePath, Strings.format(json, version));
         Files.move(tempFilePath, fileSettingsService.watchedFile(), StandardCopyOption.ATOMIC_MOVE);
     }
 

x-pack/plugin/watcher/src/internalClusterTest/java/org/elasticsearch/xpack/watcher/transform/TransformIntegrationTests.java

@@ -68,7 +68,7 @@ public class TransformIntegrationTests extends AbstractWatcherIntegrationTestCas
             // When using the MockScriptPlugin we can map File scripts to inline scripts:
             // the name of the file script is used in test method while the source of the file script
             // must match a predefined script from CustomScriptPlugin.pluginScripts() method
-            Files.write(scripts.resolve("my-script.mockscript"), "['key3' : ctx.payload.key1 + ctx.payload.key2]".getBytes("UTF-8"));
+            Files.writeString(scripts.resolve("my-script.mockscript"), "['key3' : ctx.payload.key1 + ctx.payload.key2]");
         } catch (final IOException e) {
             throw new UncheckedIOException(e);
         }

x-pack/qa/evil-tests/src/test/java/org/elasticsearch/xpack/security/authc/kerberos/SimpleKdcLdapServer.java

@@ -25,7 +25,6 @@ import java.io.IOException;
 import java.net.DatagramSocket;
 import java.net.InetAddress;
 import java.net.ServerSocket;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.security.AccessController;
@@ -154,7 +153,7 @@ public class SimpleKdcLdapServer {
             + "admin_pw=secret\n"
             + "base_dn="
             + baseDn;
-        Files.write(this.workDir.resolve("backend.conf"), backendConf.getBytes(StandardCharsets.UTF_8));
+        Files.writeString(this.workDir.resolve("backend.conf"), backendConf);
         assert Files.exists(this.workDir.resolve("backend.conf"));
     }
 

x-pack/qa/security-tools-tests/src/test/java/org/elasticsearch/xpack/security/support/SecurityFilesTests.java

@@ -15,7 +15,6 @@ import org.elasticsearch.test.ESTestCase;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
-import java.nio.charset.StandardCharsets;
 import java.nio.file.FileSystem;
 import java.nio.file.FileVisitResult;
 import java.nio.file.Files;
@@ -52,7 +51,7 @@ public class SecurityFilesTests extends ESTestCase {
         boolean supportsPosixPermissions = Environment.getFileStore(path).supportsFileAttributeView(PosixFileAttributeView.class);
         assumeTrue("Ignoring because posix file attributes are not supported", supportsPosixPermissions);
 
-        Files.write(path, "foo".getBytes(StandardCharsets.UTF_8));
+        Files.writeString(path, "foo");
 
         Set<PosixFilePermission> perms = Sets.newHashSet(OWNER_READ, OWNER_WRITE);
         if (randomBoolean()) perms.add(OWNER_EXECUTE);
@@ -78,7 +77,7 @@ public class SecurityFilesTests extends ESTestCase {
     public void testFailure() throws IOException {
         final Path path = createTempFile("existing", "file");
 
-        Files.write(path, "foo".getBytes(StandardCharsets.UTF_8));
+        Files.writeString(path, "foo");
 
         final Visitor innerVisitor = new Visitor(path);
         final RuntimeException re = expectThrows(
@@ -138,8 +137,8 @@ public class SecurityFilesTests extends ESTestCase {
         try (FileSystem fs = Jimfs.newFileSystem(jimFsConfiguration)) {
             Path path = fs.getPath("foo");
             Path tempPath = fs.getPath("bar");
-            Files.write(path, "foo".getBytes(StandardCharsets.UTF_8));
+            Files.writeString(path, "foo");
-            Files.write(tempPath, "bar".getBytes(StandardCharsets.UTF_8));
+            Files.writeString(tempPath, "bar");
 
             PosixFileAttributeView view = Files.getFileAttributeView(path, PosixFileAttributeView.class);
             view.setGroup(fs.getUserPrincipalLookupService().lookupPrincipalByGroupName(randomAlphaOfLength(10)));