N.J. Ct. R. 3:16

(a) Pretrial. The defendant must be present for every scheduled event unless excused by the court for good cause shown.

(b) At Trial or Post-conviction Proceedings. The defendant shall be present at every stage of the trial, including the impaneling of the jury and the return of the verdict, and at the imposition of sentence, unless otherwise provided by Rule. Nothing in this Rule, however, shall prevent a defendant from waiving the right to be present at trial. A waiver may be found either from (a) the defendant's express written or oral waiver placed on the record, or (b) the defendant's conduct evidencing a knowing, voluntary, and unjustified absence after (1) the defendant has received actual notice in court or has signed a written acknowledgment of the trial date, or (2) trial has commenced in defendant's presence. A corporation shall appear by its attorney for all purposes. The defendant's presence is not required at a reduction of sentence under R. 3:21-10 or, except as provided in R. 3:22-10, at a hearing on a petition for post conviction relief.