N.J. Stat. Ann. § 2A:50-3

The obligor in any bond or note specified in section 2A:50-2 of this Title, with respect to any bond given after March 29, 1933, and with respect to any note given after the effective date of this amendatory act may file an answer in the action for deficiency, disputing the amount of the deficiency sued for. In that event both parties may introduce evidence as to the fair market value of the mortgaged premises at the time of the sale thereof in the foreclosure action, and the court, with or without a jury, shall determine the amount of such deficiency, by deducting from the debt secured the amount determined as the fair market value of the premises. If all parties to the action shall so agree, the court may accept as the fair market value of the mortgaged premises the value fixed by three appraisers, to be named by agreement of all the parties to the action, which agreement shall be evidenced by a stipulation to be filed in the action.