diff --git a/runtime/Dart/lib/antlr4.dart b/runtime/Dart/lib/antlr4.dart
index 9b69169a6d..60ae882be4 100644
--- a/runtime/Dart/lib/antlr4.dart
+++ b/runtime/Dart/lib/antlr4.dart
@@ -8,20 +8,24 @@ library antlr4;
 
 export 'src/atn/atn.dart';
 export 'src/dfa/dfa.dart';
-export 'src/tree/tree.dart';
 export 'src/error/error.dart';
-export 'src/rule_context.dart';
+export 'src/misc/misc.dart';
+export 'src/tree/tree.dart';
+
 export 'src/input_stream.dart';
-export 'src/token_stream.dart';
+export 'src/interval_set.dart';
 export 'src/lexer.dart';
 export 'src/parser.dart';
 export 'src/parser_rule_context.dart';
-export 'src/vocabulary.dart';
-export 'src/runtime_meta_data.dart';
-export 'src/token.dart';
 export 'src/prediction_context.dart';
 export 'src/recognizer.dart';
-export 'src/interval_set.dart';
+export 'src/rule_context.dart';
+export 'src/runtime_meta_data.dart';
+export 'src/token.dart';
+export 'src/token_factory.dart';
+export 'src/token_source.dart';
+export 'src/token_stream.dart';
+export 'src/vocabulary.dart';
 
 import 'src/util/platform_stub.dart'
     if (dart.library.io) 'src/util/platform_io.dart';
diff --git a/runtime/Dart/lib/src/atn/src/atn_config_set.dart b/runtime/Dart/lib/src/atn/src/atn_config_set.dart
index 874eef6534..0c6de03e0c 100644
--- a/runtime/Dart/lib/src/atn/src/atn_config_set.dart
+++ b/runtime/Dart/lib/src/atn/src/atn_config_set.dart
@@ -9,7 +9,7 @@ import 'dart:math';
 
 import 'package:collection/collection.dart';
 
-import '../../misc/pair.dart';
+import '../../misc/misc.dart';
 import '../../prediction_context.dart';
 import '../../util/bit_set.dart';
 import '../../util/utils.dart';
diff --git a/runtime/Dart/lib/src/atn/src/atn_deserializer.dart b/runtime/Dart/lib/src/atn/src/atn_deserializer.dart
index ee6928be10..67de5abd2c 100644
--- a/runtime/Dart/lib/src/atn/src/atn_deserializer.dart
+++ b/runtime/Dart/lib/src/atn/src/atn_deserializer.dart
@@ -5,7 +5,7 @@
  */
 
 import '../../interval_set.dart';
-import '../../misc/pair.dart';
+import '../../misc/misc.dart';
 import '../../token.dart';
 import 'atn.dart';
 import 'atn_state.dart';
diff --git a/runtime/Dart/lib/src/atn/src/parser_atn_simulator.dart b/runtime/Dart/lib/src/atn/src/parser_atn_simulator.dart
index 2555190d9f..062ff6fd27 100644
--- a/runtime/Dart/lib/src/atn/src/parser_atn_simulator.dart
+++ b/runtime/Dart/lib/src/atn/src/parser_atn_simulator.dart
@@ -13,7 +13,7 @@ import '../../dfa/dfa.dart';
 import '../../error/error.dart';
 import '../../input_stream.dart';
 import '../../interval_set.dart';
-import '../../misc/pair.dart';
+import '../../misc/misc.dart';
 import '../../parser.dart';
 import '../../parser_rule_context.dart';
 import '../../prediction_context.dart';
diff --git a/runtime/Dart/lib/src/error/src/error_strategy.dart b/runtime/Dart/lib/src/error/src/error_strategy.dart
index b418c13af8..a751545695 100644
--- a/runtime/Dart/lib/src/error/src/error_strategy.dart
+++ b/runtime/Dart/lib/src/error/src/error_strategy.dart
@@ -10,7 +10,7 @@ import 'package:logging/logging.dart';
 
 import '../../atn/atn.dart';
 import '../../interval_set.dart';
-import '../../misc/pair.dart';
+import '../../misc/misc.dart';
 import '../../parser.dart';
 import '../../parser_rule_context.dart';
 import '../../rule_context.dart';
diff --git a/runtime/Dart/lib/src/lexer.dart b/runtime/Dart/lib/src/lexer.dart
index 3b3bc67cbf..2520f827d5 100644
--- a/runtime/Dart/lib/src/lexer.dart
+++ b/runtime/Dart/lib/src/lexer.dart
@@ -10,7 +10,7 @@ import 'atn/atn.dart';
 import 'error/error.dart';
 import 'input_stream.dart';
 import 'interval_set.dart';
-import 'misc/pair.dart';
+import 'misc/misc.dart';
 import 'recognizer.dart';
 import 'token.dart';
 import 'token_factory.dart';
@@ -33,7 +33,16 @@ abstract class Lexer extends Recognizer<LexerATNSimulator>
   late Pair<TokenSource, CharStream?> _tokenFactorySourcePair;
 
   @override
-  TokenFactory tokenFactory = CommonTokenFactory.DEFAULT;
+  TokenFactory get tokenFactory {
+    return _factory;
+  }
+
+  @override
+  set tokenFactory(TokenFactory factory) {
+    _factory = factory;
+  }
+
+  TokenFactory _factory = CommonTokenFactory.DEFAULT;
 
   /// The goal of all lexer rules/methods is to create a token object.
   /// this is an instance variable as multiple rules may collaborate to
diff --git a/runtime/Dart/lib/src/misc/misc.dart b/runtime/Dart/lib/src/misc/misc.dart
new file mode 100644
index 0000000000..73829bf6ef
--- /dev/null
+++ b/runtime/Dart/lib/src/misc/misc.dart
@@ -0,0 +1,8 @@
+/*
+ * Copyright (c) 2012-2023 The ANTLR Project. All rights reserved.
+ * Use of this file is governed by the BSD 3-clause license that
+ * can be found in the LICENSE.txt file in the project root.
+ */
+
+export 'src/multi_map.dart';
+export 'src/pair.dart';
diff --git a/runtime/Dart/lib/src/misc/multi_map.dart b/runtime/Dart/lib/src/misc/src/multi_map.dart
similarity index 100%
rename from runtime/Dart/lib/src/misc/multi_map.dart
rename to runtime/Dart/lib/src/misc/src/multi_map.dart
diff --git a/runtime/Dart/lib/src/misc/pair.dart b/runtime/Dart/lib/src/misc/src/pair.dart
similarity index 94%
rename from runtime/Dart/lib/src/misc/pair.dart
rename to runtime/Dart/lib/src/misc/src/pair.dart
index 4993dc289f..50a9c2160c 100644
--- a/runtime/Dart/lib/src/misc/pair.dart
+++ b/runtime/Dart/lib/src/misc/src/pair.dart
@@ -4,7 +4,7 @@
  * can be found in the LICENSE.txt file in the project root.
  */
 
-import '../util/murmur_hash.dart';
+import '../../util/murmur_hash.dart';
 
 class Pair<A, B> {
   final A a;
diff --git a/runtime/Dart/lib/src/parser_interpreter.dart b/runtime/Dart/lib/src/parser_interpreter.dart
index 6ddf105eb0..92aca69318 100644
--- a/runtime/Dart/lib/src/parser_interpreter.dart
+++ b/runtime/Dart/lib/src/parser_interpreter.dart
@@ -9,7 +9,7 @@ import 'dart:collection';
 import 'atn/atn.dart';
 import 'dfa/dfa.dart';
 import 'error/error.dart';
-import 'misc/pair.dart';
+import 'misc/misc.dart';
 import 'parser.dart';
 import 'parser_rule_context.dart';
 import 'token.dart';
diff --git a/runtime/Dart/lib/src/prediction_context.dart b/runtime/Dart/lib/src/prediction_context.dart
index 11b601ea74..cd0965440c 100644
--- a/runtime/Dart/lib/src/prediction_context.dart
+++ b/runtime/Dart/lib/src/prediction_context.dart
@@ -7,7 +7,7 @@
 import 'package:collection/collection.dart';
 
 import 'atn/atn.dart';
-import 'misc/pair.dart';
+import 'misc/misc.dart';
 import 'recognizer.dart';
 import 'rule_context.dart';
 import 'util/murmur_hash.dart';
diff --git a/runtime/Dart/lib/src/token.dart b/runtime/Dart/lib/src/token.dart
index 442dba9fb2..d60ec032d0 100644
--- a/runtime/Dart/lib/src/token.dart
+++ b/runtime/Dart/lib/src/token.dart
@@ -6,7 +6,7 @@
 
 import 'input_stream.dart';
 import 'interval_set.dart';
-import 'misc/pair.dart';
+import 'misc/misc.dart';
 import 'token_source.dart';
 
 /// A token has properties: text, type, line, character position in the line
diff --git a/runtime/Dart/lib/src/token_factory.dart b/runtime/Dart/lib/src/token_factory.dart
index 832368091f..1e12f11994 100644
--- a/runtime/Dart/lib/src/token_factory.dart
+++ b/runtime/Dart/lib/src/token_factory.dart
@@ -6,7 +6,7 @@
 
 import 'input_stream.dart';
 import 'interval_set.dart';
-import 'misc/pair.dart';
+import 'misc/misc.dart';
 import 'token.dart';
 import 'token_source.dart';
 
diff --git a/runtime/Dart/lib/src/token_source.dart b/runtime/Dart/lib/src/token_source.dart
index bbf0ee43ec..14bdb6418d 100644
--- a/runtime/Dart/lib/src/token_source.dart
+++ b/runtime/Dart/lib/src/token_source.dart
@@ -7,7 +7,7 @@
 import 'dart:math';
 
 import 'input_stream.dart';
-import 'misc/pair.dart';
+import 'misc/misc.dart';
 import 'token.dart';
 import 'token_factory.dart';
 
diff --git a/runtime/Dart/lib/src/tree/src/pattern/parse_tree_match.dart b/runtime/Dart/lib/src/tree/src/pattern/parse_tree_match.dart
index 87e709eca1..c8adeeac71 100644
--- a/runtime/Dart/lib/src/tree/src/pattern/parse_tree_match.dart
+++ b/runtime/Dart/lib/src/tree/src/pattern/parse_tree_match.dart
@@ -7,7 +7,7 @@
 import '../../../error/error.dart';
 import '../../../input_stream.dart';
 import '../../../lexer.dart';
-import '../../../misc/multi_map.dart';
+import '../../../misc/misc.dart';
 import '../../../parser.dart';
 import '../../../parser_interpreter.dart';
 import '../../../parser_rule_context.dart';