It is never explicitly stated or even implied in the films that 'James Bond' is a code name, and there is little to nothing in the films to indicate the code name idea is valid. However, there is not in the novels at all, which are about an agent whose real name is James Bond. Some have even claimed that this is an idea from the novels.
Over the years, some fans have come up with the idea that there is no one 'James Bond,' that it's merely a code name assigned to a series of agents, as a way of explaining why Bond never seems to age and has continued for nearly half a century.