diff --git a/core/modules/comment/lib/Drupal/comment/Tests/CommentLinksTest.php b/core/modules/comment/lib/Drupal/comment/Tests/CommentLinksTest.php
index b269657..b312dec 100644
--- a/core/modules/comment/lib/Drupal/comment/Tests/CommentLinksTest.php
+++ b/core/modules/comment/lib/Drupal/comment/Tests/CommentLinksTest.php
@@ -157,7 +157,7 @@ function setEnvironment(array $info) {
 
         // comment_num_new() relies on history_read(), so ensure that no one has
         // seen the node of this comment.
-        $this->container->get('history.manager')->deleteByEntity('node', $this->node->id());
+        \Drupal::service('history.manager')->deleteByEntity('node', $this->node->id());
       }
       else {
         $cids = db_query("SELECT cid FROM {comment}")->fetchCol();
diff --git a/core/modules/forum/lib/Drupal/forum/ForumManager.php b/core/modules/forum/lib/Drupal/forum/ForumManager.php
index e230a22..51c573b 100644
--- a/core/modules/forum/lib/Drupal/forum/ForumManager.php
+++ b/core/modules/forum/lib/Drupal/forum/ForumManager.php
@@ -111,7 +111,7 @@ class ForumManager implements ForumManagerInterface {
   protected $translationManager;
 
   /**
-   * History manager service.
+   * The history manager service.
    *
    * @var \Drupal\history\HistoryManagerInterface
    */
diff --git a/core/modules/history/lib/Drupal/history/Controller/HistoryController.php b/core/modules/history/lib/Drupal/history/Controller/HistoryController.php
index d20178b..fc9e243 100644
--- a/core/modules/history/lib/Drupal/history/Controller/HistoryController.php
+++ b/core/modules/history/lib/Drupal/history/Controller/HistoryController.php
@@ -86,7 +86,7 @@ public function readNode(Request $request, NodeInterface $node) {
     $this->historyManager->write('node', $node->id());
 
     $history = $this->historyManager->read('node', array($node->id()));
-    return new JsonResponse((int) $history[$node->id()]);
+    return new JsonResponse($history[$node->id()]);
   }
 
 }
diff --git a/core/modules/history/lib/Drupal/history/HistoryManager.php b/core/modules/history/lib/Drupal/history/HistoryManager.php
index ab8dcdf..84ff5b5 100644
--- a/core/modules/history/lib/Drupal/history/HistoryManager.php
+++ b/core/modules/history/lib/Drupal/history/HistoryManager.php
@@ -107,7 +107,7 @@ public function purge() {
       ->condition('timestamp', HISTORY_READ_LIMIT, '<')
       ->execute();
     // Clean static cache.
-    $this->history = array();
+    $this->resetCache();
   }
 
   /**
@@ -118,7 +118,7 @@ public function deleteByUid($uid) {
       ->condition('uid', $uid)
       ->execute();
     // Clean static cache.
-    $this->history = array();
+    $this->resetCache();
   }
 
   /**
diff --git a/core/modules/history/lib/Drupal/history/HistoryManagerInterface.php b/core/modules/history/lib/Drupal/history/HistoryManagerInterface.php
index cdd040d..79e0fb3 100644
--- a/core/modules/history/lib/Drupal/history/HistoryManagerInterface.php
+++ b/core/modules/history/lib/Drupal/history/HistoryManagerInterface.php
@@ -66,7 +66,7 @@ public function deleteByUid($uid);
   public function deleteByEntity($entity_type, $entity_id);
 
   /**
-   * Reset the static cache.
+   * Resets the static cache.
    */
   public function resetCache();