Where can I get Jamaican currency?

Could you please tell me where I might be able to acquire Jamaican currency? I'm in need of some Jamaican dollars for an upcoming trip and I'm not sure of the best place to exchange my local currency for them. Are there any banks or currency exchange offices in my area that specialize in Jamaican currency? Or would it be more practical to simply withdraw the money from an ATM when I arrive in Jamaica? I'd appreciate any advice you can give on this matter.