N.J. Stat. § 3B:3-35
If a devisee who is a grandparent, stepchild or a lineal descendant of a grandparent of the decedent is dead at the time of the execution of the governing instrument, fails to survive the decedent, or is treated as if he predeceased the decedent, any descendants of the deceased devisee who survives the decedent by 120 hours take by representation in place of the deceased devisee. One who would have been a devisee under a class gift if he had survived the decedent is treated as a devisee for purposes of this section whether his death occurred before or after the execution of the governing instrument. For purposes of this section, a"stepchild" means a child of the surviving, deceased or former spouse who is not a child of the decedent.
N.J.S. § 3B:3-35