I haven't been able to get a straight answer can your carry or even own a collapsible baton in New Jersey, if so do i need a permit?
You can own one and even carry one as long as you have a lawful purpose to have it. Sounds like a risky thing to do to me. There are several other states that have a similar law including Pennsylvania.
Check out http://www.my-self-defense.com/new-jersey-expandable-baton-laws.html to read the law on expandable batons in New Jersey.
I am not providing any legal advice. I suggest consulting an attorney regarding this if you plan to carry in NJ.