Symfony\Component\Routing\Loader\AnnotationClassLoader::getDefaultRouteName PHP Method

    protected function getDefaultRouteName(\ReflectionClass $class, \ReflectionMethod $method)
    {
        return strtolower(str_replace('\\', '_', $class->getName()).'_'.$method->getName());
    }

 /**
  * {@inheritdoc}
  */
 protected function getDefaultRouteName(\ReflectionClass $class, \ReflectionMethod $method)
 {
     $routeName = parent::getDefaultRouteName($class, $method);
     return preg_replace(['/(bundle|controller)_/', '/action(_\\d+)?$/', '/__/'], ['_', '\\1', '_'], $routeName);
 }