N.J. Stat. § 40:65-4: Publication of notice where service impossible

If the owner is unknown, or if, for any reason, service cannot be made as hereinbefore directed, the notice shall be published in a newspaper circulating in the municipality, at least once and not less than thirty days before the improvement is made by the municipality. Notices to the owner or owners of several distinct parcels of real estate may be inserted in the same publication.