Under New Jersey law, any person arrested for a crime (felony), disorderly or petty disorderly persons offense (misdemeanor), or municipal ordinance violation, where it was discharged without conviction may apply for an expungement at any time after the disposition of the criminal proceedings. Once that expungement is issued, if anyone asks if you have ever been arrested, you can honestly say, "No!"
The one exception is where you were arrested for drug possession, and the charge was ultimately dismissed due to a Conditional Discharge. That situation is a little different. Where the charges were dismissed after the successful completion of a supervisory treatment program, you have to wait at least six months following the dismissal of the charges.
If you live here in southern New Jersey and are looking to "clean up your act" and get the skeletons out of your closet, I may be able to be of assistance. Please feel free to call me at 856-432-4113 or contact me through this site to schedule a free consultation in my Woodbury office to discuss your situation.