RFR: 8350546: Several java/net/InetAddress tests fails UnknownHostException [v4]

[Daniel Fuchs]

On Mon, 3 Mar 2025 12:49:30 GMT, Jaikiran Pai <jpai at openjdk.org> wrote:

>> SendaoYan has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Remove "@build jtreg.SkippedException"
>
> test/jdk/java/net/InetAddress/IsReachableViaLoopbackTest.java line 63:
> 
>> 61:         } catch (java.net.UnknownHostException e) {
>> 62:             e.printStackTrace();
>> 63:             throw new SkippedException("Network setup issue");
> 
> I am wondering for tests like these two whether we should introduce a JDK specific `@key` (in `TEST.ROOT`) https://openjdk.org/jtreg/tag-spec.html and then have these 2 tests use that key to indicate that these tests require an external connection. That way, when launching jtreg you can specify that it skip executing these tests based on that key name.
> 
> Daniel, Aleksei, would there be some other better way to deal with this?

I wouldn't be surprised to see this test randomly fail with `RuntimeException(remoteAddr + " is reachable")` on some configurations as it depends on how "`localhost"` gets resolved on the local machine (even if that's another issue). AFAICS it's trying to test that remote addresses are not reachable from the loopback. But `InetAddress.getByName("localhost")` may not always return the loopback. Using `InetAddress.getLoopbackAddress()` would be more robust. And maybe we could use `getByAddress()` instead of `getByName()` for the remote address, which would avoid the UnknownHostException?

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PR Review Comment: https://git.openjdk.org/jdk/pull/23767#discussion_r1977611349