diff --git a/core/includes/config.inc b/core/includes/config.inc
index b92c741..0444a91 100644
--- a/core/includes/config.inc
+++ b/core/includes/config.inc
@@ -1,7 +1,7 @@
 <?php
 
 use Drupal\Core\Config\Config;
-use Drupal\Core\Config\ConfigException;
+use Drupal\Core\Config\Config\ConfigException;
 use Drupal\Core\Config\FileStorage;
 use Drupal\Core\Config\NullStorage;
 use Drupal\Core\Config\StorageInterface;
@@ -114,16 +114,11 @@ function config_sync_get_changes(StorageInterface $source_storage, StorageInterf
  *   The storage to synchronize configuration from.
  * @param Drupal\Core\Config\StorageInterface $target_storage
  *   The storage to synchronize configuration to.
- *
- * @throws Drupal\Core\Config\ConfigException
  */
 function config_sync_changes(array $config_changes, StorageInterface $source_storage, StorageInterface $target_storage) {
   foreach (array('delete', 'create', 'change') as $op) {
     foreach ($config_changes[$op] as $name) {
-      // Bail out if the configuration object is not namespaced by extension.
-      if (strpos($name, '.') === FALSE) {
-        throw new ConfigException(sprintf('Missing namespace in Config name %s', $name));
-      }
+      Config::checkNamespace($name);
       if ($op == 'delete') {
         $target_storage->delete($name);
       }
@@ -186,8 +181,6 @@ function config_import() {
  * @param Drupal\Core\Config\StorageInterface $target_storage
  *   The storage to synchronize configuration to.
  *
- * @throws Drupal\Core\Config\ConfigException
- *
  * @todo Add support for other extension types; e.g., themes etc.
  */
 function config_import_invoke_owner(array $config_changes, StorageInterface $source_storage, StorageInterface $target_storage) {
@@ -197,10 +190,7 @@ function config_import_invoke_owner(array $config_changes, StorageInterface $sou
   // handle dependencies correctly.
   foreach (array('delete', 'create', 'change') as $op) {
     foreach ($config_changes[$op] as $key => $name) {
-      // Bail out if the configuration object is not namespaced by extension.
-      if (strpos($name, '.') === FALSE) {
-        throw new ConfigException(sprintf('Missing namespace in Config name %s', $name));
-      }
+      Config::checkNamespace($name);
       // Extract owner from configuration object name.
       $module = strtok($name, '.');
       // Check whether the module implements hook_config_import() and ask it to
diff --git a/core/lib/Drupal/Core/Config/Config.php b/core/lib/Drupal/Core/Config/Config.php
index 4f1474d..6991030 100644
--- a/core/lib/Drupal/Core/Config/Config.php
+++ b/core/lib/Drupal/Core/Config/Config.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\Config;
 
+use Drupal\Core\Config\ConfigException;
 use Drupal\Component\Utility\NestedArray;
 
 /**
@@ -289,14 +290,11 @@ class Config {
   /**
    * Saves the configuration object.
    *
-   * @throws Drupal\Core\Config\ConfigException
    */
   public function save() {
     // All configuration objects need to be namespaced by extension, as it would
     // be impossible to maintain them otherwise.
-    if (strpos($this->name, '.') === FALSE) {
-      throw new ConfigException(sprintf('Missing namespace in Config name %s', $this->name));
-    }
+    $this->checkNamespace($this->name);
     $this->sortByKey($this->data);
     $this->storage->write($this->name, $this->data);
     $this->isNew = FALSE;
@@ -333,4 +331,15 @@ class Config {
     $this->resetOverriddenData();
     return $this;
   }
+  /**
+   * Checks if a configuration object is namespaced by extension.
+   *
+   * @throws Drupal\Core\Config\ConfigException
+   */
+  public static function checkNamespace($name)
+  {
+    if (strpos($name, '.') === FALSE) {
+      throw new ConfigException(format_string('Missing namespace in Config name @name', array('@name' => $name)));
+    }
+  }
 }