Does Kotlin support package protected visibility?

Question

In Java package protected access was very handy, because it allowed to write modular code. This is not possible with Kotlin unless you stick all those classes into one file and put Private on all of them or by implementing Internal in a separate Module. But I don't like this solutions. Putting lot of stuff in one file is not readable and another problem is that you cannot test any Method/Class that is not Public. Is there another solution?

Answer 1

No, package-protected access is not supported.

You should use internal in Kotlin. This restricts access to the same module, a logical unit of files compiled together to an artifact.

The motivation for not providing a package-protected visibility specifier is as follows, from a Kotlin developer:

The motivation for not having package protected access is very simple: it does not provide any real encapsulation. Any other module in the system can define classes in the same package as your complex independent component and get full access to its internals. On the other hand, classes with internal visibility cannot be accessed from any module other than the one where they are defined.

And you definitely can test methods/classes that have internal access: the tests of a module have full access to internal declarations of that module.