RFR: 8302845: Replace finalizer usage in JNDI DNS provider with Cleaner

[Alan Bateman]

On Fri, 5 May 2023 17:25:38 GMT, Aleksei Efimov <aefimov at openjdk.org> wrote:

> JNDI `DnsClient` has a finalize method to close its internal datagram channel selector.
>  The change proposed here replaces it with a cleaner to close the selector once the `DnsClient`
>   instance becomes phantom reachable. 
> 
> The change was tested with `jdk-tier1` to `jdk-tier3` test sets which showed no failures.

src/jdk.naming.dns/share/classes/com/sun/jndi/dns/DnsClient.java line 163:

> 161:         }
> 162:         // register a cleaning action to close the channel
> 163:         // selector when this DNS client becomes phantom reachable

The change looks okay, it's just the comment here isn't quite right, it should say "to close the Selector when ...".

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

PR Review Comment: https://git.openjdk.org/jdk/pull/13837#discussion_r1186377852