This is problem solvable a few different ways. The first step is determine what your lease (if you have one) says. Some leases contain "walk-through" clauses, which essentially state that you accept the space "as-is." If this is the case, the landlord will say you should have thoroughly inspected the premises before occupying. Whether this holds up in front of a judge is a much different story. Concealing a latent defect (like a roach infestation) could be a failure of consideration, which could free you of your obligation. It also raises the potential for some nasty other claims against the landlord.
Another avenue you may pursue is "occupying" but withholding rent until the landlord fixes the roach problem. This process can be lengthy.
You may also send notice to your landlord of the condition and advise him that if he doesn't treat the apartment you will do so at your own expense and deduct the cost from your second month rent.
All of your options turn on how bad the roach problem is. Unfortunately, finding one or two dead roaches in your apartment , while concerning, probably isn't enough to walk away.
Best of luck with your situation.
I agree with Mr. Major.
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Concur with Attorney Major and would only add that in most states (NJ too), there is a process for withholding rent, demanding extermination of pests etc. If you don't follow the process in your state you MAY lose the privilege of recovering damages, rent already paid, and terminating the lease agreement and more. Make sure the steps you take after possession transfers to you on Dec 1st are IAW NJ statutes.
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