N.J. Stat. Ann. § 43:13-22.31

From and after the adoption of this act any employee who is or becomes a member of the retirement system created hereby may not withdraw therefrom and shall not be entitled to a refund of any of the moneys therefrom and thereafter deducted from his salary hereunder; provided, however, that any employee who is separated from the municipal service through discharge, resignation, or for any reasons other than retirement, except as hereinafter stated, shall be entitled to a refund of his contributions.