diff --git a/core/lib/Drupal/Core/Plugin/Discovery/AnnotatedClassDiscovery.php b/core/lib/Drupal/Core/Plugin/Discovery/AnnotatedClassDiscovery.php
index 84cb550..d15696a 100644
--- a/core/lib/Drupal/Core/Plugin/Discovery/AnnotatedClassDiscovery.php
+++ b/core/lib/Drupal/Core/Plugin/Discovery/AnnotatedClassDiscovery.php
@@ -17,19 +17,24 @@ class AnnotatedClassDiscovery extends ComponentAnnotatedClassDiscovery {
   /**
    * Constructs an AnnotatedClassDiscovery object.
    *
+   * @param string $owner
+   *   The module name that defines the plugin type.
+   * @param string $type
+   *   The plugin type, for example filter.
+   * @param array $root_namespaces
+   *
    * @param array $plugin_namespaces
    *   An array of paths keyed by it's corresponding namespaces.
    */
-  function __construct($owner, $type, $root_namespaces = NULL, array $plugin_namespaces = array()) {
+  function __construct($owner, $type, array $root_namespaces = array(), array $plugin_namespaces = array()) {
     $this->owner = $owner;
     $this->type = $type;
     $this->rootNamespaces = $root_namespaces;
-    $this->pluginNamespaces = $plugin_namespaces;
     $annotation_namespaces = array(
       'Drupal\Component\Annotation' => DRUPAL_ROOT . '/core/lib',
       'Drupal\Core\Annotation' => DRUPAL_ROOT . '/core/lib',
     );
-    parent::__construct(array(), $annotation_namespaces, 'Drupal\Core\Annotation\Plugin');
+    parent::__construct($plugin_namespaces, $annotation_namespaces, 'Drupal\Core\Annotation\Plugin');
   }
 
   /**
@@ -41,7 +46,7 @@ function __construct($owner, $type, $root_namespaces = NULL, array $plugin_names
    * lifetime of a plugin manager.
    */
   protected function getPluginNamespaces() {
-    if (!empty($this->plugin_namespaces)) {
+    if (!empty($this->pluginNamespaces)) {
       return parent::getPluginNamespaces();
     }
     $plugin_namespaces = array();
diff --git a/core/modules/system/lib/Drupal/system/Tests/Plugin/Discovery/AnnotatedClassDiscoveryTest.php b/core/modules/system/lib/Drupal/system/Tests/Plugin/Discovery/AnnotatedClassDiscoveryTest.php
index eb08a1a..11ae638 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Plugin/Discovery/AnnotatedClassDiscoveryTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Plugin/Discovery/AnnotatedClassDiscoveryTest.php
@@ -57,5 +57,20 @@ public function setUp() {
     $this->discovery = new AnnotatedClassDiscovery('plugin_test', 'fruit', $namespaces);
     $this->emptyDiscovery = new AnnotatedClassDiscovery('non_existing_module', 'non_existing_plugin_type', $namespaces);
   }
+
+  /**
+   * Tests AnnotatedClassDiscovery without root namespaces.
+   */
+  public function testAnnotatedClassDiscoveryWithPluginNamespaces() {
+    $plugin_namespaces = array();
+    $plugin_namespaces['Drupal\\plugin_test\\Plugin\\plugin_test\\fruit'] = array(DRUPAL_ROOT . '/core/modules/system/tests/modules/plugin_test/lib');
+    $this->discovery = new AnnotatedClassDiscovery('plugin_test', 'fruit', array(), $plugin_namespaces);
+    $plugin_namespaces = array();
+    $plugin_namespaces['Drupal\\plugin_test\\Plugin\\non_existing_module\\non_existing_plugin_type'] = array(DRUPAL_ROOT . '/core/modules/system/tests/modules/plugin_test/lib');
+    $this->emptyDiscovery = new AnnotatedClassDiscovery('non_existing_module', 'non_existing_plugin_type', array(), $plugin_namespaces);
+
+    $this->testDiscoveryInterface();
+  }
+
 }