Hello World!

Hello World (Example Drupal 8 Controller) code:

<?php
namespace Drupal\helloworld\Controller;
use Drupal\Core\Controller\ControllerBase;

class DefaultController extends ControllerBase {
  public function hello() {
    return [
      '#type' => 'markup',
      '#markup' => $this->t('Hello World (Example Drupal 8 Controller) code!')
    ];
  }
}