Can't get File Owner using Google Drive API
<p>Trying to find the owner of a file by getting the permissions for the file, looping through them, and retrieving the user information (specifically the email address) of the permission with the role of "owner".</p>

<pre><code>PermissionList filePermissions = service.permissions().list(fileID).execute();

for (Permission permission : filePermissions) {

    if (permission.getRole().toLowerCase().equals("owner")) {
        String fileOwner = permission.getEmailAddress();
    }

}
</code></pre>

<p>"permission.getEmailAddress()" kept returning <strong>null</strong>, so I decided to call "toPrettyString()" on every permission and it showed that the permission objects only consistently contained the "id", "kind", "role", and "type", but never "emailAddress".</p>

<p>The <a href="https://developers.google.com/drive/v3/reference/permissions#resource" rel="nofollow">Google documentation for the Drive API</a> lists "emailAddress" as one of the properties for permission objects, so I'm confused as to why I can't retrieve it.</p>

<p>I thought it might be related to the user credentials used to get the Drive Service, but even using the credentials of the file owner still yeilds the same results.</p>