...
Finally, since it is very rare that generally universally acceptable truth would exist, therefore it is worth to note that there are cases when both of the two rules above should be broken. One such case is the data object, traveling between the client and the server (or vice versa). There, it is not just well but even wished that the object be serialized upon sending, and deserialized upon receiving. There are general frameworks that use getters and setters during the serialization and deserialization. In this case it is allowed to "expose" implementation details - after all, we're not dealing with business processes right now, we have to take care of mere technical problems, namely transferring data from one computer (e.g. the server) to another (e.g. the client). So it's actually not breaking of any of the rules above. However, in these cases, extra care should be taken to avoid the misuse of these getters and setters - they are only for sending and receiving information, and not for any other purposes.