N.J. Stat. § 54:3-3
The members shall be appointed for a term of three years and until their successors shall have been duly appointed and qualified. If there happens to be any vacancy in said office, during the recess of the Legislature, caused by reason of death, resignation or in any manner other than by the expiration of the term for which any person shall have been appointed, the Governor shall fill such a vacancy and the commission shall expire at the end of the next session of the Legislature unless a successor shall be sooner appointed. In filling vacancies other than those that have been created during the recess of the Legislature as herein provided for the Governor shall appoint with the advice and consent of the Senate for the unexpired term only. The members of the county boards of taxation in counties of the first class who are in office at the time this act (s. 54:3-2, s. 54:3-3 and s. 54:3-22.1) becomes effective shall, without further appointment or confirmation, continue in office for the balance of the term for which they and each of them were respectively appointed. The term of office of the members hereafter appointed by the Governor by and with the advice and consent of the Senate shall be five years and until their successors shall have been duly appointed and qualified; provided, however, that of the two additional members to be added, the term of one shall expire April thirtieth, one thousand nine hundred and forty-four, and the other April thirtieth, one thousand nine hundred and forty-five; and provided, further, that they shall continue in office until their respective successors shall have been duly appointed and qualified.
N.J.S. § 54:3-3