tl;dr it's fine for music or directions in my opinion (not a lawyer) but not for answering phone calls or texting.

Technically, the NJ MVC rules state that for drivers with a GDL or probational license (so, a step up from learners permit) aren't allowed to use a cellphone, not even hands-free. If CarPlay counts as hands-free phone usage, you're not allowed to use it. However, CarPlay for GPS or music is probably fine since that's not prohibited, and this is just how your car gets access to directions/music. You probably shouldn't be answering any phone calls, not even hands-free though.

>Use of a cell phone (hand-held or hands-free), hand-held video games or any other hand-held wireless electronic devices (i.e., ipods, GPS) is prohibited.

Source: https://www.state.nj.us/mvcbiz/pdf/About/GDLBrochure.pdf