N.J. Stat. § 2A:18-54
Where for any reason, any of the notices required by section 2A:18-53 of this title, cannot be served as provided in said section or a summons and complaint cannot be served as in other actions, such notices or summons and complaint may be served upon any person actually occupying the premises, either personally or by leaving same with a member of his family above the age of 14 years, or when admission to the premises is denied or the tenant or occupant and all members of his family above the age of 14 years are absent from the premises, or there is no person actually occupying them, the officer or other person may post or affix a copy of the same upon the door or other conspicuous part of such premises. Such posting shall be deemed to be lawful service.
N.J.S. § 2A:18-54