Support building on JDK 21

builtins/src/main/java/org/jline/builtins/Completers.java

@@ -446,6 +446,7 @@ public TreeCompleter(Node... nodes) {
             this(Arrays.asList(nodes));
         }
 
+        @SuppressWarnings("this-escape")
         public TreeCompleter(List<Node> nodes) {
             StringBuilder sb = new StringBuilder();
             addRoots(sb, nodes);

builtins/src/main/java/org/jline/builtins/Nano.java

@@ -1551,6 +1551,7 @@ public Nano(Terminal terminal, Path root, Options opts) {
         this(terminal, root, opts, null);
     }
 
+    @SuppressWarnings("this-escape")
     public Nano(Terminal terminal, Path root, Options opts, ConfigurationPath configPath) {
         this.terminal = terminal;
         this.windowsTerminal = terminal.getClass().getSimpleName().endsWith("WinSysTerminal");

builtins/src/main/java/org/jline/builtins/Tmux.java

@@ -428,6 +428,7 @@ public void resizePane(Options opt, int adjust) {
         }
     }
 
+    @SuppressWarnings("this-escape")
     public Tmux(Terminal terminal, PrintStream err, Consumer<Terminal> runner) throws IOException {
         this.terminal = terminal;
         this.err = err;

console/src/main/java/org/jline/console/impl/Builtins.java

@@ -74,6 +74,7 @@ public Builtins(Supplier<Path> workDir, ConfigurationPath configPath, Function<S
         this(null, workDir, configPath, widgetCreator);
     }
 
+    @SuppressWarnings("this-escape")
     public Builtins(
             Set<Command> commands,
             Supplier<Path> workDir,

console/src/main/java/org/jline/console/impl/ConsoleEngineImpl.java

@@ -87,7 +87,7 @@ public ConsoleEngineImpl(ScriptEngine engine, Printer printer, Supplier<Path> wo
         this(null, engine, printer, workDir, configPath);
     }
 
-    @SuppressWarnings("unchecked")
+    @SuppressWarnings({"unchecked", "this-escape"})
     public ConsoleEngineImpl(
             Set<Command> commands,
             ScriptEngine engine,

console/src/main/java/org/jline/console/impl/SystemRegistryImpl.java

@@ -81,6 +81,7 @@ public enum Pipe {
     private boolean commandGroups = true;
     private Function<CmdLine, CmdDesc> scriptDescription;
 
+    @SuppressWarnings("this-escape")
     public SystemRegistryImpl(Parser parser, Terminal terminal, Supplier<Path> workDir, ConfigurationPath configPath) {
         this.parser = parser;
         this.workDir = workDir;

console/src/main/java/org/jline/widget/AutopairWidgets.java

@@ -68,6 +68,7 @@ public AutopairWidgets(LineReader reader) {
         this(reader, false);
     }
 
+    @SuppressWarnings("this-escape")
     public AutopairWidgets(LineReader reader, boolean addCurlyBrackets) {
         super(reader);
         if (existsWidget(AP_INSERT)) {

console/src/main/java/org/jline/widget/AutosuggestionWidgets.java

@@ -22,6 +22,7 @@
 public class AutosuggestionWidgets extends Widgets {
     private boolean enabled = false;
 
+    @SuppressWarnings("this-escape")
     public AutosuggestionWidgets(LineReader reader) {
         super(reader);
         if (existsWidget("_autosuggest-forward-char")) {

console/src/main/java/org/jline/widget/TailTipWidgets.java

@@ -124,6 +124,7 @@ public TailTipWidgets(LineReader reader, Function<CmdLine, CmdDesc> descFun, int
         this(reader, null, descriptionSize, tipType, descFun);
     }
 
+    @SuppressWarnings("this-escape")
     private TailTipWidgets(
             LineReader reader,
             Map<String, CmdDesc> tailTips,

groovy/src/main/java/org/jline/script/GroovyCommand.java

@@ -51,6 +51,7 @@ public GroovyCommand(GroovyEngine engine, Printer printer) {
         this(null, engine, printer);
     }
 
+    @SuppressWarnings("this-escape")
     public GroovyCommand(Set<Command> commands, GroovyEngine engine, Printer printer) {
         this.engine = engine;
         this.printer = printer;

pom.xml

@@ -109,7 +109,7 @@
         <gogo.jline.version>1.1.8</gogo.jline.version>
         <slf4j.version>2.0.6</slf4j.version>
         <findbugs.version>3.0.2</findbugs.version>
-        <groovy.version>4.0.7</groovy.version>
+        <groovy.version>4.0.13</groovy.version>
         <ivy.version>2.5.1</ivy.version>
         <graal.version>22.3.0</graal.version>
         <graal.plugin.version>21.2.0</graal.plugin.version>
@@ -522,7 +522,7 @@
                 <plugin>
                     <groupId>com.diffplug.spotless</groupId>
                     <artifactId>spotless-maven-plugin</artifactId>
-                    <version>2.28.0</version>
+                    <version>2.37.0</version>
                     <configuration>
                         <java>
                             <toggleOffOn />
@@ -684,11 +684,6 @@
                 <groupId>org.graalvm.nativeimage</groupId>
                 <artifactId>native-image-maven-plugin</artifactId>
             </plugin>
-
-            <plugin>
-                <groupId>com.diffplug.spotless</groupId>
-                <artifactId>spotless-maven-plugin</artifactId>
-            </plugin>
         </plugins>
     </build>
 
@@ -764,6 +759,21 @@
             </build>
         </profile>
 
+        <profile>
+            <id>java11</id>
+            <activation>
+                <jdk>[11,21)</jdk>
+            </activation>
+            <build>
+                <plugins>
+                    <plugin>
+                        <groupId>com.diffplug.spotless</groupId>
+                        <artifactId>spotless-maven-plugin</artifactId>
+                    </plugin>
+                </plugins>
+            </build>
+        </profile>
+
         <profile>
             <id>license-check</id>
             <build>

reader/src/main/java/org/jline/reader/impl/LineReaderImpl.java

@@ -232,7 +232,7 @@ protected enum BellType {
 
     protected KillRing killRing = new KillRing();
 
-    protected UndoTree<Buffer> undo = new UndoTree<>(this::setBuffer);
+    protected UndoTree<Buffer> undo;
     protected boolean isUndo;
 
     /**
@@ -291,6 +291,7 @@ public LineReaderImpl(Terminal terminal, String appName) throws IOException {
         this(terminal, appName, null);
     }
 
+    @SuppressWarnings("this-escape")
     public LineReaderImpl(Terminal terminal, String appName, Map<String, Object> variables) {
         Objects.requireNonNull(terminal, "terminal can not be null");
         this.terminal = terminal;
@@ -309,6 +310,7 @@ public LineReaderImpl(Terminal terminal, String appName, Map<String, Object> var
             this.alternateOut = Curses.tputs(terminal.getStringCapability(Capability.exit_alt_charset_mode));
         }
 
+        undo = new UndoTree<>(this::setBuffer);
         builtinWidgets = builtinWidgets();
         widgets = new HashMap<>(builtinWidgets);
         bindingReader = new BindingReader(terminal.reader());

reader/src/main/java/org/jline/reader/impl/UndoTree.java

@@ -20,6 +20,7 @@ public class UndoTree<T> {
     private final Node parent;
     private Node current;
 
+    @SuppressWarnings("this-escape")
     public UndoTree(Consumer<T> s) {
         state = s;
         parent = new Node(null);

reader/src/main/java/org/jline/reader/impl/history/DefaultHistory.java

@@ -43,6 +43,7 @@ public class DefaultHistory implements History {
 
     public DefaultHistory() {}
 
+    @SuppressWarnings("this-escape")
     public DefaultHistory(LineReader reader) {
         attach(reader);
     }

remote-telnet/src/main/java/org/jline/builtins/telnet/ConnectionData.java

@@ -81,6 +81,7 @@ public class ConnectionData {
      * @param sock Socket of the inbound connection.
      * @param cm the connection manager
      */
+    @SuppressWarnings("this-escape")
     public ConnectionData(Socket sock, ConnectionManager cm) {
         socket = sock;
         connectionManager = cm;

remote-telnet/src/main/java/org/jline/builtins/telnet/ConnectionManager.java

@@ -74,6 +74,7 @@ public abstract class ConnectionManager implements Runnable {
     private boolean lineMode = false;
     private boolean stopping = false;
 
+    @SuppressWarnings("this-escape")
     public ConnectionManager() {
         threadGroup = new ThreadGroup(toString() + "Connections");
         closedConnections = new Stack<Connection>();

terminal/src/main/java/org/jline/terminal/Attributes.java

@@ -137,6 +137,7 @@ public enum LocalFlag {
 
     public Attributes() {}
 
+    @SuppressWarnings("this-escape")
     public Attributes(Attributes attr) {
         copy(attr);
     }

terminal/src/main/java/org/jline/terminal/Size.java

@@ -15,6 +15,7 @@ public class Size {
 
     public Size() {}
 
+    @SuppressWarnings("this-escape")
     public Size(int columns, int rows) {
         this();
         setColumns(columns);

terminal/src/main/java/org/jline/terminal/impl/AbstractTerminal.java

@@ -44,19 +44,21 @@ public abstract class AbstractTerminal implements Terminal {
     protected final Set<Capability> bools = new HashSet<>();
     protected final Map<Capability, Integer> ints = new HashMap<>();
     protected final Map<Capability, String> strings = new HashMap<>();
-    protected final ColorPalette palette = new ColorPalette(this);
+    protected final ColorPalette palette;
     protected Status status;
     protected Runnable onClose;
 
     public AbstractTerminal(String name, String type) throws IOException {
         this(name, type, null, SignalHandler.SIG_DFL);
     }
 
+    @SuppressWarnings("this-escape")
     public AbstractTerminal(String name, String type, Charset encoding, SignalHandler signalHandler)
             throws IOException {
         this.name = name;
         this.type = type != null ? type : "ansi";
         this.encoding = encoding != null ? encoding : Charset.defaultCharset();
+        this.palette = new ColorPalette(this);
         for (Signal signal : Signal.values()) {
             handlers.put(signal, signalHandler);
         }

terminal/src/main/java/org/jline/terminal/impl/AbstractWindowsTerminal.java

@@ -82,6 +82,7 @@ public abstract class AbstractWindowsTerminal<Console> extends AbstractTerminal
     protected boolean focusTracking = false;
     private volatile boolean closing;
 
+    @SuppressWarnings("this-escape")
     public AbstractWindowsTerminal(
             Writer writer,
             String name,

terminal/src/main/java/org/jline/terminal/impl/DumbTerminal.java

@@ -40,6 +40,7 @@ public DumbTerminal(String name, String type, InputStream in, OutputStream out,
         this(name, type, in, out, encoding, SignalHandler.SIG_DFL);
     }
 
+    @SuppressWarnings("this-escape")
     public DumbTerminal(
             String name, String type, InputStream in, OutputStream out, Charset encoding, SignalHandler signalHandler)
             throws IOException {

terminal/src/main/java/org/jline/terminal/impl/ExternalTerminal.java

@@ -67,6 +67,7 @@ public ExternalTerminal(
         this(name, type, masterInput, masterOutput, encoding, signalHandler, paused, null, null);
     }
 
+    @SuppressWarnings("this-escape")
     public ExternalTerminal(
             String name,
             String type,

terminal/src/main/java/org/jline/terminal/impl/LineDisciplineTerminal.java

@@ -91,6 +91,7 @@ public LineDisciplineTerminal(String name, String type, OutputStream masterOutpu
         this(name, type, masterOutput, encoding, SignalHandler.SIG_DFL);
     }
 
+    @SuppressWarnings("this-escape")
     public LineDisciplineTerminal(
             String name, String type, OutputStream masterOutput, Charset encoding, SignalHandler signalHandler)
             throws IOException {

terminal/src/main/java/org/jline/terminal/impl/PosixPtyTerminal.java

@@ -55,6 +55,7 @@ public PosixPtyTerminal(
         this(name, type, pty, in, out, encoding, signalHandler, false);
     }
 
+    @SuppressWarnings("this-escape")
     public PosixPtyTerminal(
             String name,
             String type,

terminal/src/main/java/org/jline/terminal/impl/PosixSysTerminal.java

@@ -34,6 +34,7 @@ public class PosixSysTerminal extends AbstractPosixTerminal {
     protected final Map<Signal, Object> nativeHandlers = new HashMap<>();
     protected final Task closer;
 
+    @SuppressWarnings("this-escape")
     public PosixSysTerminal(
             String name, String type, Pty pty, Charset encoding, boolean nativeSignals, SignalHandler signalHandler)
             throws IOException {

terminal/src/main/java/org/jline/utils/ColorPalette.java

@@ -42,6 +42,7 @@ public ColorPalette(Terminal terminal) throws IOException {
         this(terminal, null);
     }
 
+    @SuppressWarnings("this-escape")
     public ColorPalette(Terminal terminal, String distance) throws IOException {
         this.terminal = terminal;
         this.distanceName = distance;

terminal/src/main/java/org/jline/utils/Display.java

@@ -41,6 +41,7 @@ public class Display {
     protected final boolean delayedWrapAtEol;
     protected final boolean cursorDownIsNewLine;
 
+    @SuppressWarnings("this-escape")
     public Display(Terminal terminal, boolean fullscreen) {
         this.terminal = terminal;
         this.fullScreen = fullscreen;

terminal/src/main/java/org/jline/utils/Status.java

@@ -39,6 +39,7 @@ public static Status getStatus(Terminal terminal, boolean create) {
         return terminal instanceof AbstractTerminal ? ((AbstractTerminal) terminal).getStatus(create) : null;
     }
 
+    @SuppressWarnings("this-escape")
     public Status(AbstractTerminal terminal) {
         this.terminal = Objects.requireNonNull(terminal, "terminal can not be null");
         this.supported = terminal.getStringCapability(Capability.change_scroll_region) != null