N.J. Stat. Ann. § 20:3-35

Any action hereunder may be abandoned at any time before or within 30 days after the filing of the award of commissioners; or in the event of an appeal from such award, at any time before or within 30 days after the entry of judgment; or in the event that a hearing before commissioners shall have been waived, at any time before or within 30 days after judgment has been entered in said action; provided, however, that no such action shall be abandoned after the filing of a declaration of taking pursuant to Article V hereof, or after the vesting of title in any condemnor pursuant hereto; and provided further, that (a) a discharge of the notice of lis pendens is filed, and (b) the condemnor shall pay the expenses of all condemnees who have appeared in the action. Nothing herein shall preclude abandonment at any time by mutual consent of the parties.