diff --git a/src/Symfony/Component/Serializer/Extractor/ObjectPropertyListExtractor.php b/src/Symfony/Component/Serializer/Extractor/ObjectPropertyListExtractor.php
index 922094f8cb..2ea19d28fa 100644
--- a/src/Symfony/Component/Serializer/Extractor/ObjectPropertyListExtractor.php
+++ b/src/Symfony/Component/Serializer/Extractor/ObjectPropertyListExtractor.php
@@ -15,8 +15,10 @@ use Symfony\Component\PropertyInfo\PropertyListExtractorInterface;
 
 /**
  * @author David Maicher <mail@dmaicher.de>
+ *
+ * @experimental in 4.3
  */
-class ObjectPropertyListExtractor implements ObjectPropertyListExtractorInterface
+final class ObjectPropertyListExtractor implements ObjectPropertyListExtractorInterface
 {
     private $propertyListExtractor;
     private $objectClassResolver;
diff --git a/src/Symfony/Component/Serializer/Extractor/ObjectPropertyListExtractorInterface.php b/src/Symfony/Component/Serializer/Extractor/ObjectPropertyListExtractorInterface.php
index 1dd9b8b99a..fd60e1e506 100644
--- a/src/Symfony/Component/Serializer/Extractor/ObjectPropertyListExtractorInterface.php
+++ b/src/Symfony/Component/Serializer/Extractor/ObjectPropertyListExtractorInterface.php
@@ -13,6 +13,8 @@ namespace Symfony\Component\Serializer\Extractor;
 
 /**
  * @author David Maicher <mail@dmaicher.de>
+ *
+ * @experimental in 4.3
  */
 interface ObjectPropertyListExtractorInterface
 {