Notice of such application, and of the day appointed for its hearing, must be issued by the judge of probate to the parties in interest who are residents of this state, which must be served on them at least five days before the day appointed for the hearing; and if any of the parties in interest are nonresidents, such notice must be given by publication, once a week for three successive weeks, in some newspaper published in the county, or if no newspaper is published therein, then in one that is published in an adjoining county, a copy of which shall be mailed by the judge of probate, and directed to such nonresidents at their post offices, if the same are known, or can be ascertained by reasonable effort.