N.J. Stat. § 43:10-18.67
From and after January 1, 1949, any employee who is or becomes a member of this retirement system may not withdraw therefrom and shall not be entitled to a refund of any moneys theretofore and thereafter deducted from his salary hereunder; provided, however that any employee who separates from the county service through his discharge, resignation, or for any reasons other than retirement, shall be entitled to a refund of all moneys theretofore deducted from his salary for the retirement system established hereunder; and provided further, that where the service of an employee is terminated by death of the employee, if such employee leaves no widow, widower, or children under 18 years of age all moneys theretofore deducted from his salary for the retirement system established hereunder shall be paid, to the person designated by the employee or in the absence of any designation, to the estate of the deceased employee.
N.J.S. § 43:10-18.67