Issue #3337096: Settings form Validation error,...

Issue #3337096: Settings form Validation error, Drupal\filefield_sources_jsonapi\Plugin\FilefieldSource\RemoteJSONAPI::jsoanApiSourceValidateRequired() cannot be called statically

src/Plugin/FilefieldSource/RemoteJSONAPI.php

@@ -462,7 +462,7 @@ class RemoteJSONAPI extends Remote {
       '#title' => t('JSON API settings'),
       '#description' => t('Defined JSON API settings at <a href=":url">manage JSON API sources</a> page.', [':url' => Url::fromRoute('entity.filefield_sources_jsonapi.collection')->toString()]),
       '#default_value' => $settings['source_remote_jsonapi']['sources'] ?: NULL,
-      '#element_validate' => [[get_called_class(), 'jsoanApiSourceValidateRequired']],
+      '#element_validate' => [[get_called_class(), 'jsonApiSourceValidateRequired']],
     ];
     $return['source_remote_jsonapi']['image_style'] = [
       '#type' => 'select',
@@ -485,7 +485,7 @@ class RemoteJSONAPI extends Remote {
   /**
    * Custom validation for JSON API source.
    */
-  public function jsoanApiSourceValidateRequired($element, FormStateInterface $form_state) {
+  public static function jsonApiSourceValidateRequired($element, FormStateInterface $form_state) {
     // Go 2 levels up.
     $parents = array_slice($element['#parents'], 0, count($element['#parents']) - 2, TRUE);
     $input = NestedArray::getValue($form_state->getValues(), $parents);