diff --git a/lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php b/lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php
index 9e081d43e..f79eda8b9 100644
--- a/lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php
+++ b/lib/Doctrine/ORM/Mapping/ClassMetadataFactory.php
@@ -526,4 +526,12 @@ class ClassMetadataFactory extends AbstractClassMetadataFactory
     {
         return $this->driver;
     }
+
+    /**
+     * {@inheritDoc}
+     */
+    protected function isEntity(ClassMetadataInterface $class)
+    {
+        return isset($class->isMappedSuperclass) && $class->isMappedSuperclass === false;
+    }
 }