My landlord is converting the building I live in into condos. Is it true that he has to give me 3 years before I have to vacate?

This issue is more complicated than other grounds for eviction. There are additional protections for protected tenants -- protected tenants are generally disabled tenants and elderly tenants. There are also several technical requirements the landlord must meet to be able to do this. The landlord will most certainly have an attorney so you should consult with an attorney about this. Tenants also have a right to request relocation assistance and could also get 5 one year eviction stays. You would have many rights and options to weigh in this situation. It will all depend on how much you want to stay in the unit, what the rent is, if there are suitable alternatives and whether this is something where you might want a payment from the landlord to leave. These will all have to be weighed in the dollar cost and benefit to you before deciding. This type of matter is best handled by an attorney because there are a number of legal issues that could and will arise.

You should review NJSA 2A:18-61.1k for notice and other requirements.