Mark many classes as final

* This fixes this-escape warnings from Java 21.
* It can also lead to save some footprint on JVM and faster analysis on SVM.

Author: eregon

src/main/java/org/truffleruby/RubyContext.java

@@ -97,7 +97,7 @@
 import com.oracle.truffle.api.source.Source;
 import sun.misc.SignalHandler;
 
-public class RubyContext {
+public final class RubyContext {
 
     private final RubyLanguage language;
     @CompilationFinal private TruffleLanguage.Env env;

src/main/java/org/truffleruby/cext/ValueWrapperManager.java

@@ -38,7 +38,7 @@
 import com.oracle.truffle.api.library.ExportMessage;
 
 @SuppressFBWarnings("VO")
-public class ValueWrapperManager {
+public final class ValueWrapperManager {
 
     static final long UNSET_HANDLE = -2L;
 
@@ -207,7 +207,7 @@ public synchronized void addFreeBlock(long blockBase) {
         }
     }
 
-    public static class HandleBlock {
+    public static final class HandleBlock {
 
         private final long base;
         private final ValueWrapperWeakReference[] wrappers;

src/main/java/org/truffleruby/core/CoreLibrary.java

@@ -99,7 +99,7 @@
  * code, it should be done at the top of the Ruby class.)
  * </ul>
  */
-public class CoreLibrary {
+public final class CoreLibrary {
 
     public static final SourceSection UNAVAILABLE_SOURCE_SECTION = Source
             .newBuilder(TruffleRuby.LANGUAGE_ID, "", "(unavailable)")

src/main/java/org/truffleruby/core/DataObjectFinalizationService.java

@@ -33,7 +33,9 @@
 
 /** C-ext data finalizers are implemented with phantom references and reference queues, and are run in a dedicated Ruby
  * thread. */
-public class DataObjectFinalizationService extends ReferenceProcessingService<DataObjectFinalizerReference, Object> {
+public final class DataObjectFinalizationService
+        extends
+        ReferenceProcessingService<DataObjectFinalizerReference, Object> {
 
     // We need a base node here, it should extend ruby base root node and implement internal root node.
     public static class DataObjectFinalizerRootNode extends RubyBaseRootNode implements InternalRootNode {

src/main/java/org/truffleruby/core/FinalizationService.java

@@ -21,7 +21,7 @@
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 
 /** Finalizers are implemented with phantom references and reference queues, and are run in a dedicated Ruby thread. */
-public class FinalizationService extends ReferenceProcessingService<FinalizerReference, Object> {
+public final class FinalizationService extends ReferenceProcessingService<FinalizerReference, Object> {
 
     static class Finalizer {
 

src/main/java/org/truffleruby/core/MarkingService.java

@@ -33,7 +33,7 @@
  *
  * Marker references only keep a week reference to their owning object to ensure they don't themselves stop the object
  * from being garbage collected. */
-public class MarkingService {
+public final class MarkingService {
 
     public static interface MarkerAction {
         public abstract void mark(Object owner);

src/main/java/org/truffleruby/core/ReferenceProcessingService.java

@@ -68,17 +68,17 @@ public ReferenceProcessingService<R, T> service() {
         }
     }
 
-    public static class ReferenceProcessor {
-        protected final ReferenceQueue<Object> processingQueue = new ReferenceQueue<>();
+    public static final class ReferenceProcessor {
+        final ReferenceQueue<Object> processingQueue = new ReferenceQueue<>();
 
-        protected RubyThread processingThread;
-        protected final RubyContext context;
+        private RubyThread processingThread;
+        private final RubyContext context;
 
         public ReferenceProcessor(RubyContext context) {
             this.context = context;
         }
 
-        protected void processReferenceQueue(ReferenceProcessingService<?, ?> service) {
+        void processReferenceQueue(ReferenceProcessingService<?, ?> service) {
             if (processOnMainThread()) {
                 drainReferenceQueues();
             } else {
@@ -102,7 +102,7 @@ public boolean processOnMainThread() {
         private static final String THREAD_NAME = "Ruby-reference-processor";
 
         @TruffleBoundary
-        protected void createProcessingThread(ReferenceProcessingService<?, ?> service) {
+        private void createProcessingThread(ReferenceProcessingService<?, ?> service) {
             final ThreadManager threadManager = context.getThreadManager();
             final RubyLanguage language = context.getLanguageSlow();
             RubyThread newThread;
@@ -126,7 +126,7 @@ protected void createProcessingThread(ReferenceProcessingService<?, ?> service)
         }
 
         @TruffleBoundary
-        protected final void drainReferenceQueues() {
+        void drainReferenceQueues() {
             final RubyLanguage language = context.getLanguageSlow();
             while (true) {
                 @SuppressWarnings("unchecked")

src/main/java/org/truffleruby/core/encoding/EncodingManager.java

@@ -44,7 +44,7 @@
 
 /** Always use {@link Encoding#getIndex()} for encoding indices. Never use
  * {@link org.jcodings.EncodingDB.Entry#getIndex()}. */
-public class EncodingManager {
+public final class EncodingManager {
 
     private RubyEncoding[] ENCODING_LIST_BY_ENCODING_INDEX = new RubyEncoding[INITIAL_NUMBER_OF_ENCODINGS];
     private final Map<String, RubyEncoding> LOOKUP = new ConcurrentHashMap<>();

src/main/java/org/truffleruby/core/exception/CoreExceptions.java

@@ -50,7 +50,7 @@
 import org.truffleruby.language.library.RubyStringLibrary;
 import org.truffleruby.language.objects.LogicalClassNode;
 
-public class CoreExceptions {
+public final class CoreExceptions {
 
     private final RubyLanguage language;
     private final RubyContext context;

src/main/java/org/truffleruby/core/fiber/FiberManager.java

@@ -45,7 +45,7 @@
 import org.truffleruby.language.objects.shared.SharedObjects;
 
 /** Helps managing Ruby {@code Fiber} objects. Only one per {@link RubyContext}. */
-public class FiberManager {
+public final class FiberManager {
 
     public static final String NAME_PREFIX = "Ruby Fiber";
     public static final Object[] SAFEPOINT_ARGS = new Object[]{ FiberSafepointMessage.class };