diff --git a/core/lib/Drupal/Core/Batch/Batch.php b/core/lib/Drupal/Core/Batch/Batch.php
index 6c124fd..0c6b340 100644
--- a/core/lib/Drupal/Core/Batch/Batch.php
+++ b/core/lib/Drupal/Core/Batch/Batch.php
@@ -41,21 +41,21 @@ class Batch {
    *
    * @var string
    */
-  protected $init_message;
+  protected $initMessage;
 
   /**
    * The message to be shown while the batch is in progress.
    *
    * @var string
    */
-  protected $progress_message;
+  protected $progressMessage;
 
   /**
    * The message to be shown if a problem occurs.
    *
    * @var string
    */
-  protected $error_message;
+  protected $errorMessage;
 
   /**
    * The name of a function / method to be called when the batch finishes.
@@ -86,7 +86,7 @@ class Batch {
    *
    * @var array
    */
-  protected $url_options = [];
+  protected $urlOptions = [];
 
   /**
    * Specifies if the batch is progressive.
@@ -150,10 +150,65 @@ public static function createFromTitle($title) {
    *   A new initialized object.
    */
   public static function createFromArray(array $batch_definition) {
-    $new_batch = new static(isset($batch_definition['title']) ? $batch_definition['title'] : NULL);
+    $new_batch = self::create();
 
-    foreach ($batch_definition as $key => $value) {
-      $new_batch->{$key} = $value;
+    if (isset($batch_definition['operations'])) {
+      foreach ($batch_definition['operations'] as list($callback, $arguments)) {
+        $new_batch->addOperation($callback, $arguments);
+      }
+    }
+
+    if (isset($batch_definition['title'])) {
+      $new_batch->setTitle($batch_definition['title']);
+    }
+
+    if (isset($batch_definition['init_message'])) {
+      $new_batch->setInitMessage($batch_definition['init_message']);
+    }
+
+    if (isset($batch_definition['progress_message'])) {
+      $new_batch->setProgressMessage($batch_definition['progress_message']);
+    }
+
+    if (isset($batch_definition['error_message'])) {
+      $new_batch->setErrorMessage($batch_definition['error_message']);
+    }
+
+    if (isset($batch_definition['finished'])) {
+      $new_batch->setFinishCallback($batch_definition['finished']);
+    }
+
+    if (isset($batch_definition['file'])) {
+      $new_batch->setFile($batch_definition['file']);
+    }
+
+    if (isset($batch_definition['css'])) {
+      if (is_array($batch_definition['css'])) {
+        $new_batch->setCss($batch_definition['css']);
+      }
+      else {
+        $new_batch->addCss($batch_definition['css']);
+      }
+    }
+
+    if (isset($batch_definition['url_options'])) {
+      $new_batch->setUrlOptions($batch_definition['url_options']);
+    }
+
+    if (isset($batch_definition['progressive'])) {
+      $new_batch->setProgressive($batch_definition['progressive']);
+    }
+
+    if (isset($batch_definition['queue'])) {
+      if (
+        isset($batch_definition['queue']['name']) &&
+        isset($batch_definition['queue']['class'])
+      ) {
+        $new_batch->setQueue(
+          $batch_definition['queue']['name'],
+          $batch_definition['queue']['class']
+        );
+      }
     }
 
     return $new_batch;
@@ -196,7 +251,7 @@ public function setFinishCallback($callback) {
    * @return $this
    */
   public function setInitMessage($message) {
-    $this->init_message = $message;
+    $this->initMessage = $message;
     return $this;
   }
 
@@ -211,7 +266,7 @@ public function setInitMessage($message) {
    * @return $this
    */
   public function setProgressMessage($message) {
-    $this->progress_message = $message;
+    $this->progressMessage = $message;
     return $this;
   }
 
@@ -224,7 +279,7 @@ public function setProgressMessage($message) {
    * @return $this
    */
   public function setErrorMessage($message) {
-    $this->error_message = $message;
+    $this->errorMessage = $message;
     return $this;
   }
 
@@ -271,7 +326,7 @@ public function setCss(array $filenames) {
    * @see \Drupal\Core\Url
    */
   public function setUrlOptions(array $options = []) {
-    $this->url_options = $options;
+    $this->urlOptions = $options;
     return $this;
   }
 
@@ -368,20 +423,19 @@ public function enqueue() {
    *   The array representation of the object.
    */
   public function toArray() {
-    $array = [];
-    foreach ($this as $key => $value) {
-      if (!is_null($value)) {
-        $array[$key] = $value;
-      }
-      else {
-        switch ($key) {
-          case 'operations':
-          case 'css':
-          case 'url_options':
-            $array[$key] = [];
-        }
-      }
-    }
+    $array = [
+      'operations' => $this->operations ?: [],
+      'title' => $this->title ?: '',
+      'init_message' => $this->initMessage ?: '',
+      'progress_message' => $this->progressMessage ?: '',
+      'error_message' => $this->errorMessage ?: '',
+      'finished' => $this->finished,
+      'file' => $this->file,
+      'css' => $this->css ?: [],
+      'url_options' => $this->urlOptions ?: [],
+      'progressive' => $this->progressive,
+      'queue' => $this->queue ?: NULL,
+    ];
 
     return $array;
   }
diff --git a/core/lib/Drupal/Core/Batch/BatchQueueController.php b/core/lib/Drupal/Core/Batch/BatchQueueController.php
index 1c4e650..046da09 100644
--- a/core/lib/Drupal/Core/Batch/BatchQueueController.php
+++ b/core/lib/Drupal/Core/Batch/BatchQueueController.php
@@ -7,7 +7,7 @@
 use Drupal\Core\Database\Database;
 use Drupal\Core\Form\FormState;
 use Drupal\Core\Queue\Batch as BatchQueue;
-use Drupal\Core\BatchMemory;
+use Drupal\Core\Queue\BatchMemory;
 use Drupal\Core\StringTranslation\TranslatableMarkup;
 use Drupal\Core\Url;
 use Symfony\Component\HttpFoundation\RedirectResponse;
@@ -575,14 +575,14 @@ protected static function populateQueue($set_id = 0) {
     $batch_set = &$batch['sets'][$set_id];
 
     if (isset($batch_set['operations'])) {
-      $batch_set += array(
-        'queue' => [
+      if (empty($batch_set['queue'])) {
+        $batch_set['queue'] = [
           'name' => 'drupal_batch:' . $batch['id'] . ':' . $set_id,
           'class' => (
-            $batch['progressive'] ? BatchQueue::class : BatchMemory::class
+          $batch['progressive'] ? BatchQueue::class : BatchMemory::class
           ),
-        ],
-      );
+        ];
+      }
 
       $queue = self::getQueueForBatch($batch_set);
       $queue->createQueue();