In addition to this answer (btw, is correct). You should add the suffix ".html.twig" in case you're using the TWIG engine to render the templates.
Your should look like this
/**
* @Template("MyOwnBundle:Default:myOwnView.html.twig")
*/
public function showAction()
{
... bla bla bla
... more bla bla
}
In this case, you're forcing the showAction() to use a custom template. If the @Template() is empty, your showAction() will looking for the associated template by convention.
Hope this helps.. if not, only "decorates" a little bit more the answer.