N.J. Stat. § 38A:5-3
The acceptance of a commission or warrant in the militia shall be deemed a resignation by the person accepting the same of all other commissions or warrants held by him in the militia, provided, however, that acceptance of a commission in the State Guard in time of war or emergency shall not be so deemed a resignation.
The acceptance of a commission or warrant, or enlistment, in any of the Armed Forces of the United States, including the reserve components thereof, shall also be deemed a resignation by the person accepting the same or so enlisting of any commissions or warrants held in the militia, provided, however, that acceptance of temporary appointments while in Federal service or of a reserve commission in the same component as that in which serving in the militia shall not be so deemed a resignation.
N.J.S. § 38A:5-3