diff --git a/lib/Core/Persistence/FieldType.php b/lib/Core/Persistence/FieldType.php
index 36367ab8..9dff883c 100644
--- a/lib/Core/Persistence/FieldType.php
+++ b/lib/Core/Persistence/FieldType.php
@@ -5,7 +5,7 @@
 use eZ\Publish\Core\Persistence\FieldType as CorePersistenceFieldType;
 use eZ\Publish\SPI\Persistence\Content\FieldValue;
 
-class FieldType extends CorePersistenceFieldType
+final class FieldType extends CorePersistenceFieldType
 {
     /**
      * @param \eZ\Publish\SPI\Persistence\Content\FieldValue $fieldValue
diff --git a/lib/Core/Persistence/FieldTypeRegistry.php b/lib/Core/Persistence/FieldTypeRegistry.php
index 9a026871..81d8714e 100644
--- a/lib/Core/Persistence/FieldTypeRegistry.php
+++ b/lib/Core/Persistence/FieldTypeRegistry.php
@@ -4,7 +4,7 @@
 
 use eZ\Publish\Core\Persistence\FieldTypeRegistry as CorePersistenceFieldTypeRegistry;
 
-class FieldTypeRegistry extends CorePersistenceFieldTypeRegistry
+final class FieldTypeRegistry extends CorePersistenceFieldTypeRegistry
 {
     public function getFieldType($identifier)
     {
diff --git a/lib/Core/Search/Legacy/Query/Common/CriterionHandler/ObjectStateIdentifier.php b/lib/Core/Search/Legacy/Query/Common/CriterionHandler/ObjectStateIdentifier.php
index 7407f37c..d89af75b 100644
--- a/lib/Core/Search/Legacy/Query/Common/CriterionHandler/ObjectStateIdentifier.php
+++ b/lib/Core/Search/Legacy/Query/Common/CriterionHandler/ObjectStateIdentifier.php
@@ -15,7 +15,7 @@
  *
  * @see \Netgen\EzPlatformSearchExtra\API\Values\Content\Query\Criterion\ObjectStateIdentifier
  */
-class ObjectStateIdentifier extends CriterionHandler
+final class ObjectStateIdentifier extends CriterionHandler
 {
     /**
      * @var \eZ\Publish\SPI\Persistence\Content\Section\Handler
diff --git a/lib/Core/Search/Legacy/Query/Common/CriterionHandler/SectionIdentifier.php b/lib/Core/Search/Legacy/Query/Common/CriterionHandler/SectionIdentifier.php
index 6e951a0f..479aa8c8 100644
--- a/lib/Core/Search/Legacy/Query/Common/CriterionHandler/SectionIdentifier.php
+++ b/lib/Core/Search/Legacy/Query/Common/CriterionHandler/SectionIdentifier.php
@@ -15,7 +15,7 @@
  *
  * @see \Netgen\EzPlatformSearchExtra\API\Values\Content\Query\Criterion\SectionIdentifier
  */
-class SectionIdentifier extends CriterionHandler
+final class SectionIdentifier extends CriterionHandler
 {
     /**
      * @var \eZ\Publish\SPI\Persistence\Content\Section\Handler
diff --git a/lib/Core/Search/Solr/Query/Common/CriterionVisitor/IsFieldEmpty.php b/lib/Core/Search/Solr/Query/Common/CriterionVisitor/IsFieldEmpty.php
index 2a9ec232..ff05e82f 100644
--- a/lib/Core/Search/Solr/Query/Common/CriterionVisitor/IsFieldEmpty.php
+++ b/lib/Core/Search/Solr/Query/Common/CriterionVisitor/IsFieldEmpty.php
@@ -15,7 +15,7 @@
  *
  * @see \Netgen\EzPlatformSearchExtra\API\Values\Content\Query\Criterion\IsFieldEmpty
  */
-class IsFieldEmpty extends CriterionVisitor
+final class IsFieldEmpty extends CriterionVisitor
 {
     /**
      * @var \eZ\Publish\SPI\Persistence\Content\Type\Handler
diff --git a/lib/Core/Search/Solr/Query/Common/CriterionVisitor/ObjectStateIdentifier.php b/lib/Core/Search/Solr/Query/Common/CriterionVisitor/ObjectStateIdentifier.php
index e85317a7..ceb644db 100644
--- a/lib/Core/Search/Solr/Query/Common/CriterionVisitor/ObjectStateIdentifier.php
+++ b/lib/Core/Search/Solr/Query/Common/CriterionVisitor/ObjectStateIdentifier.php
@@ -13,7 +13,7 @@
  *
  * @see \Netgen\EzPlatformSearchExtra\API\Values\Content\Query\Criterion\ObjectStateIdentifier
  */
-class ObjectStateIdentifier extends CriterionVisitor
+final class ObjectStateIdentifier extends CriterionVisitor
 {
     /**
      * @var \eZ\Publish\SPI\Persistence\Content\ObjectState\Handler
diff --git a/lib/Core/Search/Solr/Query/Common/CriterionVisitor/SectionIdentifier.php b/lib/Core/Search/Solr/Query/Common/CriterionVisitor/SectionIdentifier.php
index 37c1bf1f..ac5b586d 100644
--- a/lib/Core/Search/Solr/Query/Common/CriterionVisitor/SectionIdentifier.php
+++ b/lib/Core/Search/Solr/Query/Common/CriterionVisitor/SectionIdentifier.php
@@ -13,7 +13,7 @@
  *
  * @see \Netgen\EzPlatformSearchExtra\API\Values\Content\Query\Criterion\SectionIdentifier
  */
-class SectionIdentifier extends CriterionVisitor
+final class SectionIdentifier extends CriterionVisitor
 {
     /**
      * @var \eZ\Publish\SPI\Persistence\Content\Section\Handler