diff --git a/core/lib/Drupal/Core/Form/FormBuilder.php b/core/lib/Drupal/Core/Form/FormBuilder.php
index c150c29..2566cf9 100644
--- a/core/lib/Drupal/Core/Form/FormBuilder.php
+++ b/core/lib/Drupal/Core/Form/FormBuilder.php
@@ -691,8 +691,8 @@ public function prepareForm($form_id, &$form, &$form_state) {
 
     $form += $this->getElementInfo('form');
     $form += array('#tree' => FALSE, '#parents' => array());
-    $form['#validate'][] = array($form_state['build_info']['callback_object'], 'validateForm');
-    $form['#submit'][] = array($form_state['build_info']['callback_object'], 'submitForm');
+    $form['#validate'][] = 'validateForm';
+    $form['#submit'][] = 'submitForm';
 
     // If no #theme has been set, automatically apply theme suggestions.
     // theme_form() itself is in #theme_wrappers and not #theme. Therefore, the
diff --git a/core/lib/Drupal/Core/Form/FormSubmitter.php b/core/lib/Drupal/Core/Form/FormSubmitter.php
index 78aca72..9496ec7 100644
--- a/core/lib/Drupal/Core/Form/FormSubmitter.php
+++ b/core/lib/Drupal/Core/Form/FormSubmitter.php
@@ -129,6 +129,10 @@ public function executeSubmitHandlers(&$form, &$form_state) {
         $batch['has_form_submits'] = TRUE;
       }
       else {
+        // Support method names of the form object by converting.
+        if (is_string($function) && method_exists($form_state['build_info']['callback_object'], $function)) {
+          $function = array($form_state['build_info']['callback_object'], $function);
+        }
         call_user_func_array($function, array(&$form, &$form_state));
       }
     }
diff --git a/core/lib/Drupal/Core/Form/FormValidator.php b/core/lib/Drupal/Core/Form/FormValidator.php
index eda8238..92cdb61 100644
--- a/core/lib/Drupal/Core/Form/FormValidator.php
+++ b/core/lib/Drupal/Core/Form/FormValidator.php
@@ -69,6 +69,10 @@ public function executeValidateHandlers(&$form, &$form_state) {
     }
 
     foreach ($handlers as $function) {
+      // Support method names of the form object by converting.
+      if (is_string($function) && method_exists($form_state['build_info']['callback_object'], $function)) {
+        $function = array($form_state['build_info']['callback_object'], $function);
+      }
       call_user_func_array($function, array(&$form, &$form_state));
     }
   }