does this retain the binary search functionality?
Yes - that's why I suggested it.
Also for ABI compat, it means that any existing code compiled with call-site compareTo(FileStatus) will continue to work, without breaking ABI from 2.8.0 -> 2.8.2.
(edit: just realized for some calls, result will now be an Object, not FileStatus - needs a cast, to assign)
As you said it used to handle non-FileStatus objects previously as not-equal.