The expected behavior from Files.walkFileTree is that if the starting path is absolute, then all the visited paths are absolute. If the starting path is relative, then all the visited paths are relative.

However, the output of Files.walkFileTree("/dir/") is something like this:

dir/file.txt
dir/dir2/another.txt
dir/dir2/
/dir/

As you can see, only the last entry is absolute. They should be consistent (in this case, they should be absolute).