N.J. Stat. § 43:15A-39
In computing for retirement purposes the total service of a member about to be retired, the retirement system shall credit the member with the time of all service rendered by the member since that member's last enrollment, and in addition with all the service to which the member is entitled and with no other service. Except as otherwise provided in this act, this service credit shall be final and conclusive for retirement purposes unless the member shall discontinue service for more than two consecutive years. In the case of a member for whom compensation is defined in paragraph (2) of subsection r. of section 6 of P.L. 1954, c.84 (C.43:15A-6), the retirement system shall credit the member with the time of all service rendered by the member during the part of any year that the member was a participant of the Defined Contribution Retirement Program, pursuant to paragraph (5) of subsection a. of section 2 of P.L. 2007, c. 92(C.43:15C-2) as amended by section 12 of P.L. 2007, c. 103, and making contributions to that program.
For the purpose of computing service for retirement purposes, the board shall fix and determine by appropriate rules and regulations how much service in any year shall equal a year of service and a part of a year of service. Not more than one year shall be credited for all service in a calendar year. A member may purchase credit for time during which the member shall have been absent on an official leave without pay. The credit shall be purchased for a period of time equal to:
The purchase shall be made in the same manner and be subject to the same terms and conditions provided for the purchase of previous membership service credit by section 8 of P.L. 1954, c.84 (C.43:15A-8). In computing the service or in computing final compensation, no time during which a member was in employment, office, or position for which the annual salary or remuneration was fixed at less than $500.00 in the case of service rendered prior to November 6, 1986, or for which the annual salary or remuneration, or the number of hours of work, is fixed at less than that which was required for membership pursuant to section 7 of P.L. 1954, c.84 (C.43:15A-7) as applicable to the member in the case of service rendered on or after that date, shall be credited. In computing the service or in computing final compensation, no time during which a member was in employment, office, or position for which the hours of work were fewer per week than those required for membership pursuant to subsection d. of section 7 of P.L. 1954, c.84 (C.43:15A-7) after the effective date of P.L. 2010, c. 1 shall be credited, unless the member shall have been a member since that effective date continuously. In the case of a veteran member credit shall be given for service rendered prior to January 2, 1955, in an employment, office or position if the annual salary or remuneration therefor was fixed at not less than $300.00 and such service consisted of the performance of the full duties of the employment, office or position.
N.J.S. § 43:15A-39