N.J. Stat. Ann. § 54:5-43

If the assessment itself is valid and the tax, assessment or other municipal charge, or any part thereof, is justly due, no sale shall be set aside, except on condition that the amount due shall be paid to the municipality for the use of the holder of the certificate of sale by the person applying to set it aside. If the sale shall be set aside, the municipality shall refund to the purchaser the price paid by him on the sale, with lawful interest, upon his assigning to the municipality the certificate of sale and all his interest in the tax, assessment or other charges and in the municipal lien therefor, and the municipality may readvertise and sell if the municipal lien remains in force.