RFR: 8313239: InetAddress.getCanonicalHostName may return ip address if reverse lookup fails [v6]

[Alan Bateman]

On Fri, 4 Aug 2023 13:01:00 GMT, Jaikiran Pai <jpai at openjdk.org> wrote:

>> Can I please get a review of this change which updates the javadoc of `java.net.InetAddress.getCanonicalHostName()` method to clarify its semantics? This addresses https://bugs.openjdk.org/browse/JDK-8313239.
>> 
>> This a javadoc only change and the documentation is updated to match the current implementation. A CSR will be drafted for this change.
>
> Jaikiran Pai has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Aleksei's review

src/java.base/share/classes/java/net/InetAddress.java line 792:

> 790:      * {@linkplain InetAddressResolver resolver}.
> 791:      *
> 792:      * <p>The system-wide resolver will be used to do a reverse name lookup of the IP address.

The wording in this paragraph seems a bit different to getHostName and I think we should try to use the same terms in both methods if possible, e.g. getHostName talks about the "system configured resolver" where here it uses "system-wide resolve". We have have "used" vs. "performed". So maybe look at the methods again as I think we should be a bit more consistent with the wording if we can.

src/java.base/share/classes/java/net/InetAddress.java line 796:

> 794:      * service. In such cases, where the resolver isn't able to determine the fully qualified
> 795:      * domain name, this method returns the {@linkplain #getHostAddress() textual representation}
> 796:      * of the IP address.

I think it would be better to say that the lookup can fail for many reasons that include the host not being registered with the name service. 

A suggestion for "In such cases .." is to say "f the resolve is unable to determine ...". I think that would be a bit easer to read.

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PR Review Comment: https://git.openjdk.org/jdk/pull/15134#discussion_r1287096421
PR Review Comment: https://git.openjdk.org/jdk/pull/15134#discussion_r1287098493