There are some revolvers that only hold 5 but most guns have the capacity for more. It's a stupid law that gives much more power to the criminals. They feel very empowered when they know they won't be outgunned by the civilians they're planning to rob.
NJ is already pretty bad with their gun laws, but if they passed a law like that, I would seriously make plans to move. At the very least I'd move to Pennsylvania and have a long commute to work.