N.J. Stat. Ann. § 43:7-11.1

A pension granted under the provisions of the act to which this act is amendatory and supplementary, shall be effective only on the first day of a month, shall be paid in equal monthly installments, and shall not be decreased, increased, revoked or repealed, except as otherwise provided by the statutory law. No pension shall be due to a member or beneficiary unless it constitutes a payment for an entire month.