You need to do some reading. First the NJ landlord Tenant Law is linked below and will be the controlling issue. Second will be your lease. If your lease and the law don't agree, the law is correct.
Chances are the owner can sell, but you will likely be able to control showings and may be entitled to the remainder of your lease. If the owner provides some incentive to leave early, consider it. I've also heard of landlords offering incentives to encourage a tenant to cooperate with showings. Consider how to make this work out for everyone.