core/lib/Drupal/Core/Installer/FullInstallerServiceProvider.php | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/core/lib/Drupal/Core/Installer/FullInstallerServiceProvider.php b/core/lib/Drupal/Core/Installer/FullInstallerServiceProvider.php
index 23f5103e21..111dd4fcbd 100644
--- a/core/lib/Drupal/Core/Installer/FullInstallerServiceProvider.php
+++ b/core/lib/Drupal/Core/Installer/FullInstallerServiceProvider.php
@@ -2,8 +2,10 @@
 
 namespace Drupal\Core\Installer;
 
+use Drupal\Core\Cache\MemoryBackendFactory;
 use Drupal\Core\DependencyInjection\ContainerBuilder;
 use Drupal\Core\DependencyInjection\ServiceProviderInterface;
+use Drupal\Core\Lock\NullLockBackend;
 
 /**
  * Service provider for the installer environment.
@@ -19,13 +21,13 @@ class FullInstallerServiceProvider implements ServiceProviderInterface {
   public function register(ContainerBuilder $container) {
     // Replace services with in-memory implementations.
     $definition = $container->getDefinition('cache_factory');
-    $definition->setClass('Drupal\Core\Cache\MemoryBackendFactory');
+    $definition->setClass(MemoryBackendFactory::class);
     $definition->setArguments([]);
     $definition->setMethodCalls([]);
 
     // Replace services with no-op implementations.
     $container
-      ->register('lock', 'Drupal\Core\Lock\NullLockBackend');
+      ->register('lock', NullLockBackend::class);
 
     // Remove the cache tags invalidator tag from the cache tags storage, so
     // that we don't call it when cache tags are invalidated very early in the