N.J. Stat. Ann. § 54:5-90

Where judgment is taken against unknown owners or claimants as provided by Rules of the Supreme Court, their equity of redemption shall be foreclosed and barred without further publication upon their failure to redeem the lands affected by the action, but notice of the date limited for redemption, the place to redeem and the amount necessary to redeem shall be posted upon the lands at least twenty days before the date so fixed. No such judgment, after it has been entered for more than five years, shall be attacked on the ground of insufficient inquiry for the identity, name or address of any defendant, his heirs, assigns or personal representatives, even though the same might have been ascertained by such inquiry.