The New Jersey sub is mostly an argument about a word. Across much of the country the long-roll sandwich travels under regional names, hoagie in Philadelphia, hero in New York, grinder in New England, wedge in Westchester, but New Jersey, sitting between the hoagie and the hero, holds firmly to "sub" and uses it for the whole format. The defining thing is less a unique recipe than a regional default the state is settled on: a long roll, split and layered the length of it, built so every bite holds the whole sandwich. What is local is the insistence on the plain word and a particular idea of what the unmodified order delivers.
It works on the same engineering as every long-roll sandwich, with New Jersey's own emphasis. The roll is the load-bearing component: a crust with enough structure to carry a long, heavy, often oil-slicked filling without folding in the middle, and an interior soft enough not to fight it. The Italian build shingles cured meats and provolone so the slices interleave and each bite gets all of them rather than a band of one at a time, then uses oil, vinegar, oregano, and shredded lettuce as a system that seasons and lubricates without dissolving the bread. Tomato is the moisture risk and goes in as part of that dressed structure so it does not flood the crumb. The state's deli density gives the format a high baseline: the roll quality and the meat slicing are where a New Jersey sub is judged, because the build itself is assumed and the execution is the whole difference.
The variations are the same roll under the state's own roster. The Italian sub shingles capicola, salami, and ham; the turkey and tuna subs keep the roll and dress and change the filling; the chicken cutlet sub runs a fried cutlet down the same bread; the hot builds treat the roll as a vessel for a saucy filling and lean on a sturdier crust. The Jersey Shore Italian sub and the Atlantic City sub are codified local readings of the same idea. Each is its own build with its own rules and deserves its own article rather than being crowded in here.