N.J. Stat. Ann. § 2A:42-10.11

In any action brought by a landlord against a tenant to recover possession of premises or units to which this act is applicable, whether by summary dispossess proceedings, civil action for the possession of land, or otherwise, judgment shall be entered for the tenant if the tenant shall establish that the notice to quit, if any, or the action to recover possession was intended for any of the reasons set forth in subsections a, b, c, or d of section 1 of this act.