N.J. Stat. § 43:1-1
Any person of the age of 40 years or over, who accepts any employment in the State or any county or municipality thereof shall not be eligible to join any pension fund maintained by the State or any county or municipality thereof, except that such person may join the pension fund established pursuant to the "Public Employees' Retirement-Social Security Integration Act," approved June 28, 1954 (P.L. 1954, c. 84), the pension fund established pursuant to "An act to provide for the creation, setting apart, maintenance and administration of a city employees' retirement system in cities of the first class having, at the time of the enactment of this act, a population in excess of 400,000 inhabitants; and merging and superseding the provisions of pension funds established pursuant to article 2 of chapter 13, chapters 18 and 19, of Title 43 of the Revised Statutes, in said cities," approved November 22, 1954 (P.L. 1954, c. 218), the pension fund created pursuant to "An act to provide for the creation, setting apart, maintenance and administration of a county employees' pension fund in counties having a population exceeding 800,000 inhabitants," approved April 8, 1943 (P.L. 1943, c. 160) or any pension fund established pursuant to article 1 of chapter 10 of Title 43 of the Revised Statutes.
This section shall not apply to "teachers" as defined in section 18:13-25 of the Title Education, nor to any person eligible to membership in the Teachers' Pension and Annuity Fund.
N.J.S. § 43:1-1