Create custom path programmatically Drupal 8

In Drupal 7, to declare path and its options, we need to implement hook_menu().
Drupal 8, create routing file in the top level module directory. If i need to create a custom path, then in custom module (myfirstcustommodule) directory create a file <modulename>.routing.yml. 
"hook_menu()" needs "page-callback" function while in Drupal 8, page callback must be either a class or a registered service. 

Drupal 7 hook_menu

<?php 
/** 
  * Implementation of hook_menu 
  */
function firstcustommodule_menu() {
$items = array();
$items['company/list'] = array(
    'title' => t('All Companies'),
    'page callback' => 'display_company_listing',
    'access callback' => TRUE,
    'type' => MENU_CALLBACK,
  );
  return $items;
}

Drupal 8

File: firstcustommodule.routing.yml

firstcustommodule.company_list:

  path: '/company/list'

  defaults:

    _controller: '\Drupal\firstcustommodule\Controller\CompanyController::getCompanyList'

    _title: 'Company Listing'

  requirements:

    _permission: 'access content'

firstcustommodule.company_list: It is route machine name. Machine name should me modulename.subname 

path:  It is the path to the page on site. It should have leading slash(/).

defaults: It describes page and title callbacks.

requirements: This having conditions under which page will be displayed. It should specify permissions, modules(on which this depends), and other conditions.

Now controller class CompanyController should be in   firstcustommodule\src\Controller\CompanyController\CompanyController.php :

<?php

/**

 * @file

 * Contains \Drupal\firstcustommodule\Controller\CompanyController

 */

namespace Drupal\firstcustommodule\Controller;

use Drupal\Core\Controller\ControllerBase;

class CompanyController extends ControllerBase {

  public function getCompanyList() {

    return [

  '#type' => 'markup',

  '#markup' => $this->t('This is company listing page by CompanyController with routing file.'),

];

  }

}

Save above created file.

Now cache clear and check this created route in browser. It looks like as in screenshot below.