The plaintiff in any action for equitable relief to which it would be necessary to make the executor of the will or administrator of the estate of a deceased person a party, if there were an executor or administrator, may, if there is no executor or administrator, and if he sets forth in his complaint the interest of such deceased person, make the deceased person’s “representatives and creditors”, without further or other designation or description, parties to the action; or if an action for equitable relief is brought relating to any interest in real property belonging to or claimed by the widow, widower or heirs of any deceased person, and the plaintiff or his attorney attach to the complaint in the action an affidavit stating that the plaintiff does not know who the widow, widower or heirs, or some of them, are, or where they or any of them reside, and, in the process to the action, describes as parties defendant “the widow and heirs”, “the widower and heirs” or “the heirs”, as the case may be, of the deceased person, without further describing the names or residences of any such parties whose names and residences may be unknown to him, the court to which the action is brought making “representatives and creditors”, “the widow and heirs”, “the widower and heirs”, or “the heirs” parties defendant, or the clerk, assistant clerk or any judge thereof, may make such order relative to the notice to be given as the court, clerk, assistant clerk or judge deems reasonable. Notice having been given according to the order and duly proved, the court may proceed to a hearing of the action. Any executor or administrator who may be appointed or qualified pending such proceedings, or any other person claiming as creditor, widow, widower or heir of the deceased person, may appear and defend in the action. All creditors and representatives of the deceased person shall be forever concluded by the judgment or decree rendered in the action.