Use Java 11 methods where possible

cli/src/main/java/hudson/cli/CLI.java

@@ -47,7 +47,6 @@
 import java.security.KeyPair;
 import java.security.SecureRandom;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -267,7 +266,7 @@ public boolean verify(String s, SSLSession sslSession) {
         }
 
         if (args.isEmpty())
-            args = Collections.singletonList("help"); // default to help
+            args = List.of("help"); // default to help
 
         if (mode == null) {
             mode = Mode.HTTP;
@@ -346,7 +345,7 @@ class Authenticator extends ClientEndpointConfig.Configurator {
             @Override
             public void beforeRequest(Map<String, List<String>> headers) {
                 if (factory.authorization != null) {
-                    headers.put("Authorization", Collections.singletonList(factory.authorization));
+                    headers.put("Authorization", List.of(factory.authorization));
                 }
             }
         }

cli/src/main/java/hudson/cli/SSHCLI.java

@@ -35,7 +35,6 @@
 import java.net.URLConnection;
 import java.security.KeyPair;
 import java.security.PublicKey;
-import java.util.Collections;
 import java.util.List;
 import java.util.Set;
 import java.util.logging.Level;
@@ -114,7 +113,7 @@ public boolean verifyServerKey(ClientSession clientSession, SocketAddress remote
                     WaitableFuture wf = channel.open();
                     wf.await();
 
-                    Set<ClientChannelEvent> waitMask = channel.waitFor(Collections.singletonList(ClientChannelEvent.CLOSED), 0L);
+                    Set<ClientChannelEvent> waitMask = channel.waitFor(List.of(ClientChannelEvent.CLOSED), 0L);
 
                     if (waitMask.contains(ClientChannelEvent.TIMEOUT)) {
                         throw new SocketTimeoutException("Failed to retrieve command result in time: " + command);

cli/src/test/java/hudson/cli/PlainCLIProtocolTest.java

@@ -157,9 +157,9 @@ void newop() throws IOException {
         while (server.stdin.size() == 0) {
             Thread.sleep(100);
         }
-        assertEquals("hello", server.stdin.toString(Charset.defaultCharset().name()));
+        assertEquals("hello", server.stdin.toString(Charset.defaultCharset()));
         assertEquals("command", server.arg);
-        assertEquals("goodbye", client.stdout.toString(Charset.defaultCharset().name()));
+        assertEquals("goodbye", client.stdout.toString(Charset.defaultCharset()));
         assertEquals(2, client.code);
     }
 

core/src/main/java/hudson/ClassicPluginStrategy.java

@@ -50,6 +50,7 @@
 import java.util.Enumeration;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 import java.util.jar.Attributes;
 import java.util.jar.JarFile;
 import java.util.jar.Manifest;
@@ -338,7 +339,7 @@ public <T> List<ExtensionComponent<T>> findComponents(Class<T> type, Hudson huds
         List<ExtensionFinder> finders;
         if (type == ExtensionFinder.class) {
             // Avoid infinite recursion of using ExtensionFinders to find ExtensionFinders
-            finders = Collections.singletonList(new ExtensionFinder.Sezpoz());
+            finders = List.of(new ExtensionFinder.Sezpoz());
         } else {
             finders = hudson.getExtensionList(ExtensionFinder.class);
         }
@@ -597,7 +598,7 @@ static final class DependencyClassLoader extends ClassLoader {
         DependencyClassLoader(ClassLoader parent, File archive, List<Dependency> dependencies, PluginManager pluginManager) {
             super(parent);
             this._for = archive;
-            this.dependencies = Collections.unmodifiableList(new ArrayList<>(dependencies));
+            this.dependencies = List.copyOf(dependencies);
             this.pluginManager = pluginManager;
         }
 
@@ -629,7 +630,7 @@ protected List<PluginWrapper> getEdges(PluginWrapper pw) {
                     for (Dependency d : dependencies) {
                         PluginWrapper p = pluginManager.getPlugin(d.shortName);
                         if (p != null && p.isActive())
-                            cgd.run(Collections.singleton(p));
+                            cgd.run(Set.of(p));
                     }
                 } catch (CycleDetectedException e) {
                     throw new AssertionError(e);    // such error should have been reported earlier

core/src/main/java/hudson/ExtensionFinder.java

@@ -560,7 +560,7 @@ protected void configure() {
             }
 
             public List<IndexItem<?, Object>> getLoadedIndex() {
-                return Collections.unmodifiableList(new ArrayList<>(loadedIndex));
+                return List.copyOf(loadedIndex);
             }
 
             @Override
@@ -645,7 +645,7 @@ private List<IndexItem<Extension, Object>> getIndices() {
             // 5. dead lock
             if (indices == null) {
                 ClassLoader cl = Jenkins.get().getPluginManager().uberClassLoader;
-                indices = Collections.unmodifiableList(StreamSupport.stream(Index.load(Extension.class, Object.class, cl).spliterator(), false).collect(Collectors.toList()));
+                indices = StreamSupport.stream(Index.load(Extension.class, Object.class, cl).spliterator(), false).collect(Collectors.toUnmodifiableList());
             }
             return indices;
         }

core/src/main/java/hudson/FilePath.java

@@ -2382,7 +2382,7 @@ private static class ReadToString extends MasterToSlaveFileCallable<String> {
 
         @Override
         public String invoke(File f, VirtualChannel channel) throws IOException, InterruptedException {
-            return new String(Files.readAllBytes(fileToPath(f)), Charset.defaultCharset());
+            return Files.readString(fileToPath(f), Charset.defaultCharset());
         }
     }
 

core/src/main/java/hudson/Functions.java

@@ -100,7 +100,6 @@
 import java.io.PrintWriter;
 import java.io.Serializable;
 import java.io.StringWriter;
-import java.io.UnsupportedEncodingException;
 import java.lang.management.LockInfo;
 import java.lang.management.ManagementFactory;
 import java.lang.management.MonitorInfo;
@@ -747,10 +746,7 @@ public static String appendSpaceIfNotNull(String n) {
     public static String nbspIndent(String size) {
         int i = size.indexOf('x');
         i = Integer.parseInt(i > 0 ? size.substring(0, i) : size) / 10;
-        StringBuilder buf = new StringBuilder(30);
-        for (int j = 2; j <= i; j++)
-            buf.append("&nbsp;");
-        return buf.toString();
+        return "&nbsp;".repeat(Math.max(0, i - 1));
     }
 
     public static String getWin32ErrorMessage(IOException e) {
@@ -777,11 +773,7 @@ public static String urlEncode(String s) {
         if (s == null) {
             return "";
         }
-        try {
-            return URLEncoder.encode(s, StandardCharsets.UTF_8.name());
-        } catch (UnsupportedEncodingException e) {
-            throw new Error(e); // impossible
-        }
+        return URLEncoder.encode(s, StandardCharsets.UTF_8);
     }
 
     public static String escape(String s) {
@@ -1933,19 +1925,19 @@ public void calcCheckUrl(Map attributes, String userDefined, Object descriptor,
      *
      * Used in {@code task.jelly} to decide if the page should be highlighted.
      */
-    public boolean hyperlinkMatchesCurrentPage(String href) throws UnsupportedEncodingException {
+    public boolean hyperlinkMatchesCurrentPage(String href) {
         String url = Stapler.getCurrentRequest().getRequestURL().toString();
         if (href == null || href.length() <= 1) return ".".equals(href) && url.endsWith("/");
-        url = URLDecoder.decode(url, "UTF-8");
-        href = URLDecoder.decode(href, "UTF-8");
+        url = URLDecoder.decode(url, StandardCharsets.UTF_8);
+        href = URLDecoder.decode(href, StandardCharsets.UTF_8);
         if (url.endsWith("/")) url = url.substring(0, url.length() - 1);
         if (href.endsWith("/")) href = href.substring(0, href.length() - 1);
 
         return url.endsWith(href);
     }
 
     public <T> List<T> singletonList(T t) {
-        return Collections.singletonList(t);
+        return List.of(t);
     }
 
     /**

core/src/main/java/hudson/PluginManager.java

@@ -930,7 +930,7 @@ public void dynamicLoad(File arc, boolean removeExisting, @CheckForNull List<Plu
                 if (batch != null) {
                     batch.add(p);
                 } else {
-                    start(Collections.singletonList(p));
+                    start(List.of(p));
                 }
 
             } catch (Exception e) {

core/src/main/java/hudson/PluginWrapper.java

@@ -174,7 +174,7 @@ public class PluginWrapper implements Comparable<PluginWrapper>, ModelObject {
     private final List<Dependency> optionalDependencies;
 
     public List<String> getDependencyErrors() {
-        return Collections.unmodifiableList(new ArrayList<>(dependencyErrors.keySet()));
+        return List.copyOf(dependencyErrors.keySet());
     }
 
     @Restricted(NoExternalUse.class) // Jelly use
@@ -222,7 +222,7 @@ public boolean hasDerivedDependencyErrors() {
      * The core can depend on a plugin if it is bundled. Sometimes it's the only thing that
      * depends on the plugin e.g. UI support library bundle plugin.
      */
-    private static Set<String> CORE_ONLY_DEPENDANT = Collections.singleton("jenkins-core");
+    private static Set<String> CORE_ONLY_DEPENDANT = Set.of("jenkins-core");
 
     /**
      * Set the list of components that depend on this plugin.

core/src/main/java/hudson/StructuredForm.java

@@ -67,7 +67,7 @@ public static List<JSONObject> toList(JSONObject parent, String propertyName) {
         if (v == null)
             return Collections.emptyList();
         if (v instanceof JSONObject)
-            return Collections.singletonList((JSONObject) v);
+            return List.of((JSONObject) v);
         if (v instanceof JSONArray)
             return (List) v;
 

core/src/main/java/hudson/WebAppMain.java

@@ -140,7 +140,7 @@ public void contextInitialized(ServletContextEvent event) {
         // Nicer console log formatting when using mvn jetty:run.
         if (Main.isDevelopmentMode && System.getProperty("java.util.logging.config.file") == null) {
             try {
-                Formatter formatter = (Formatter) Class.forName("io.jenkins.lib.support_log_formatter.SupportLogFormatter").newInstance();
+                Formatter formatter = (Formatter) Class.forName("io.jenkins.lib.support_log_formatter.SupportLogFormatter").getDeclaredConstructor().newInstance();
                 for (Handler h : Logger.getLogger("").getHandlers()) {
                     if (h instanceof ConsoleHandler) {
                         ((ConsoleHandler) h).setFormatter(formatter);

core/src/main/java/hudson/cli/CLIAction.java

@@ -277,8 +277,8 @@ void run() throws IOException, InterruptedException {
                     wait();
                 }
             }
-            PrintStream stdout = new PrintStream(streamStdout(), false, encoding.name());
-            PrintStream stderr = new PrintStream(streamStderr(), true, encoding.name());
+            PrintStream stdout = new PrintStream(streamStdout(), false, encoding);
+            PrintStream stderr = new PrintStream(streamStderr(), true, encoding);
             if (args.isEmpty()) {
                 stderr.println("Connection closed before arguments received");
                 sendExit(2);

core/src/main/java/hudson/cli/CLICommand.java

@@ -42,7 +42,6 @@
 import java.io.InputStream;
 import java.io.PrintStream;
 import java.io.UncheckedIOException;
-import java.io.UnsupportedEncodingException;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Type;
 import java.nio.charset.Charset;
@@ -415,11 +414,7 @@ public final String getSingleLineSummary() {
         } catch (InterruptedException e) {
             throw new RuntimeException(e);
         }
-        try {
-            return out.toString(charset.name());
-        } catch (UnsupportedEncodingException e) {
-            throw new AssertionError(e);
-        }
+        return out.toString(charset);
     }
 
     /**
@@ -437,11 +432,7 @@ public final String getUsage() {
         } catch (InterruptedException e) {
             throw new RuntimeException(e);
         }
-        try {
-            return out.toString(charset.name());
-        } catch (UnsupportedEncodingException e) {
-            throw new AssertionError(e);
-        }
+        return out.toString(charset);
     }
 
     /**
@@ -458,20 +449,11 @@ public final String getLongDescription() {
         } catch (InterruptedException e) {
             throw new RuntimeException(e);
         }
-        PrintStream ps;
-        try {
-            ps = new PrintStream(out, false, charset.name());
-        } catch (UnsupportedEncodingException e) {
-            throw new AssertionError(e);
-        }
+        PrintStream ps = new PrintStream(out, false, charset);
 
         printUsageSummary(ps);
         ps.close();
-        try {
-            return out.toString(charset.name());
-        } catch (UnsupportedEncodingException e) {
-            throw new AssertionError(e);
-        }
+        return out.toString(charset);
     }
 
     /**

core/src/main/java/hudson/model/AbstractBuild.java

@@ -925,7 +925,7 @@ public boolean tearDown(AbstractBuild build, BuildListener listener) throws IOEx
     @Override
     @NonNull public List<ChangeLogSet<? extends ChangeLogSet.Entry>> getChangeSets() {
         ChangeLogSet<? extends ChangeLogSet.Entry> cs = getChangeSet();
-        return cs.isEmptySet() ? Collections.emptyList() : Collections.singletonList(cs);
+        return cs.isEmptySet() ? Collections.emptyList() : List.of(cs);
     }
 
     /**
@@ -995,7 +995,7 @@ public EnvironmentList getEnvironments() {
             return new EnvironmentList(buildEnvironments);
         }
 
-        return new EnvironmentList(buildEnvironments == null ? Collections.emptyList() : Collections.unmodifiableList(new ArrayList<>(buildEnvironments)));
+        return new EnvironmentList(buildEnvironments == null ? Collections.emptyList() : List.copyOf(buildEnvironments));
     }
 
     public Calendar due() {

core/src/main/java/hudson/model/Actionable.java

@@ -31,6 +31,7 @@
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.Set;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -227,7 +228,7 @@ public boolean removeAction(@Nullable Action a) {
             return false;
         }
         // CopyOnWriteArrayList does not support Iterator.remove, so need to do it this way:
-        return getActions().removeAll(Collections.singleton(a));
+        return getActions().removeAll(Set.of(a));
     }
 
     /**

core/src/main/java/hudson/model/Descriptor.java

@@ -59,13 +59,13 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.IdentityHashMap;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -863,7 +863,7 @@ Permission getRequiredGlobalConfigPagePermission() {
     }
 
     private String getViewPage(Class<?> clazz, String pageName, String defaultValue) {
-        return getViewPage(clazz, Collections.singleton(pageName), defaultValue);
+        return getViewPage(clazz, Set.of(pageName), defaultValue);
     }
 
     private String getViewPage(Class<?> clazz, Collection<String> pageNames, String defaultValue) {
@@ -978,7 +978,7 @@ public void doHelp(StaplerRequest req, StaplerResponse rsp) throws IOException,
                 rsp.setContentType("text/html;charset=UTF-8");
                 try (InputStream in = url.openStream()) {
                     String literal = IOUtils.toString(in, StandardCharsets.UTF_8);
-                    rsp.getWriter().println(Util.replaceMacro(literal, Collections.singletonMap("rootURL", req.getContextPath())));
+                    rsp.getWriter().println(Util.replaceMacro(literal, Map.of("rootURL", req.getContextPath())));
                 }
                 return;
             }

core/src/main/java/hudson/model/DirectoryBrowserSupport.java

@@ -39,7 +39,6 @@
 import java.util.Arrays;
 import java.util.Calendar;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.Comparator;
 import java.util.GregorianCalendar;
 import java.util.LinkedHashMap;
@@ -507,10 +506,7 @@ private List<Path> buildParentPath(String pathList, int restSize) {
 
     private static String createBackRef(int times) {
         if (times == 0)    return "./";
-        StringBuilder buf = new StringBuilder(3 * times);
-        for (int i = 0; i < times; i++)
-            buf.append("../");
-        return buf.toString();
+        return "../".repeat(times);
     }
 
     private static void zip(StaplerResponse rsp, VirtualFile root, VirtualFile dir, String glob) throws IOException, InterruptedException {
@@ -764,7 +760,7 @@ private static List<List<Path>> buildChildPaths(VirtualFile cur, Locale locale)
                 for (VirtualFile f : files) {
                     Path p = new Path(Util.rawEncode(f.getName()), f.getName(), f.isDirectory(), f.length(), f.canRead(), f.lastModified());
                     if (!f.isDirectory()) {
-                        r.add(Collections.singletonList(p));
+                        r.add(List.of(p));
                     } else {
                         // find all empty intermediate directory
                         List<Path> l = new ArrayList<>();

core/src/main/java/hudson/model/DownloadService.java

@@ -388,7 +388,7 @@ public FormValidation updateNow() throws IOException {
                 }
                 String jsonString;
                 try {
-                    jsonString = loadJSONHTML(new URL(site + ".html?id=" + URLEncoder.encode(getId(), "UTF-8") + "&version=" + URLEncoder.encode(Jenkins.VERSION, "UTF-8")));
+                    jsonString = loadJSONHTML(new URL(site + ".html?id=" + URLEncoder.encode(getId(), StandardCharsets.UTF_8) + "&version=" + URLEncoder.encode(Jenkins.VERSION, StandardCharsets.UTF_8)));
                     toolInstallerMetadataExists = true;
                 } catch (Exception e) {
                     LOGGER.log(Level.FINE, "Could not load json from " + site, e);