RFR: 8353440: Disable FTP fallback for non-local file URLs by default [v6]

[Eirik Bjørsnøs]

On Wed, 23 Apr 2025 18:39:05 GMT, Daniel Fuchs <dfuchs at openjdk.org> wrote:

> The `java/net/URL/OpenStream.java` test however shows a potential compatibility issue: it was expecting `UnknownHostException` and gets `MalformedURLException` instead.
> 
> This should probably be mentioned in the compatibility risk section of the CSR, and in the release note too.

Yes, this is true. The RN/CSR currently focuses too narrowly on the happy path UNC handling, where the path exists. The not-so-happy path now changes the behavior from returning an FtpURLConnection (which may or may not succeed a connection) to unconditionally throwing a MUE.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/24657#issuecomment-2825311252