diff --git a/src/Symfony/Component/DependencyInjection/Extension/Extension.php b/src/Symfony/Component/DependencyInjection/Extension/Extension.php
index 44c95c0ba6cc0..117ee58c111f4 100644
--- a/src/Symfony/Component/DependencyInjection/Extension/Extension.php
+++ b/src/Symfony/Component/DependencyInjection/Extension/Extension.php
@@ -82,7 +82,7 @@ public function getConfiguration(array $config, ContainerBuilder $container)
         $class = $container->getReflectionClass($class);
         $constructor = $class ? $class->getConstructor() : null;
 
-        if (!$constructor || !$constructor->getNumberOfRequiredParameters()) {
+        if ($class && (!$constructor || !$constructor->getNumberOfRequiredParameters())) {
             return $class->newInstance();
         }
     }