My New Jersey employment contract guarantees two weeks notice

My employment contract with a New Jersey company says that I am an at will employee, but it also says the employer has to give me two weeks notice if I am terminated without cause. Which prevails here, the contractual obligation of two weeks notice or the fact that at will employees can be terminated without notice? I was laid off without cause and without notice, along with 200 coworkers who had the same contract as I did.