N.J. Stat. § 40:43-11
The officers of any municipality, any portion of which shall be included within the newly created municipality, who shall hold office at the time of such creation or incorporation, shall, until the organization of the governing body of such newly created municipality, continue to perform the duties and possess the powers imposed upon or given to them by law within their respective municipalities, notwithstanding the creation or incorporation of such new municipality.
On the first Monday following the first election of officers held within the newly created municipality, the terms of office of the officers of any municipality, the whole of which shall be included within the limits of such newly created municipality, shall thereupon cease and be terminated, and said officers shall forthwith deliver over to the governing body of such newly created municipality immediately after their qualification, all books, papers, assets and property of every kind and description belonging to the said old municipality.
N.J.S. § 40:43-11