Of course, Google Cloud Storage does not actually have folders. However some tools create files with names ending in "/" to pretend that the folder exists.

NIO understands that 0-byte files that end in "/" actually mean "please pretend to the user that there is a folder with that name, even though Cloud Storage doesn't have folders", and complies (there is an option to turn that behavior off).

Recently we have seen non-empty files with the same intent (see this bug report). We have to update NIO so as to keep track of the latest folder convention.