N.J. Stat. § 2A:40A-1
A covenant, promise, agreement or understanding in, or in connection with or collateral to a contract, agreement or purchase order, relative to the construction, alteration, repair, maintenance, servicing, or security of a building, structure, highway, railroad, appurtenance and appliance, including moving, demolition, excavating, grading, clearing, site preparation or development of real property connected therewith, purporting to indemnify or hold harmless the promisee against liability for damages arising out of bodily injury to persons or damage to property caused by or resulting from the sole negligence of the promisee, his agents, or employees, is against public policy and is void and unenforceable; provided that this section shall not affect the validity of any insurance contract, workmen's compensation or agreement issued by an authorized insurer.
N.J.S. § 2A:40A-1