What Happen when we call save method on collection like $collection->save();

i just try to call save method on collection function like bellow code

    class Index extends \Magento\Framework\App\Action\Action {      protected $  resultPageFactory;     private $  product;     /**      * Constructor      *      * @param \Magento\Framework\App\Action\Context  $  context      * @param \Magento\Framework\View\Result\PageFactory $  resultPageFactory      */     public function __construct(         \Magento\Framework\App\Action\Context $  context         \Magento\Catalog\Model\Product $  product,         \Magento\Framework\View\Result\PageFactory $  resultPageFactory     ) {         $  this->resultPageFactory = $  resultPageFactory;         $  this->product=$  product;         parent::__construct($  context);     }      /**      * Execute view action      *      * @return \Magento\Framework\Controller\ResultInterface      */     public function execute()     {         $  collection = $  this->product->getCollection();         var_dump($  collection->save());exit;     } } 

it not show any error just go in infinite loop …. no any error.

My Question is what actually happen it save all product or any error ?