RFR: 8350546: Several java/net/InetAddress tests fails UnknownHostException [v9]

[Daniel Fuchs]

On Tue, 4 Mar 2025 11:52:10 GMT, SendaoYan <syan at openjdk.org> wrote:

>> Hi all,
>> 
>> Two java/net/InetAddress tests fails "java.net.UnknownHostException" on some special machines. The machine cannot connect to the Internet directly and needs to be connected to the Internet through a jump machine. The java/net/InetAddress tests report "java.net.UnknownHostException: bugs.openjdk.org: Temporary failure in name resolution" failure do not caused by JVM bug but environmentalk issue, so this PR match the java.net.UnknownHostException and throw jtreg.SkippedException instead of report test fails.
>> 
>> And run the tests with JVM options `-Dhttp.proxyHost=192.168.50.1 -Dhttp.proxyPort=10991 -Dhttps.proxyHost=192.168.50.1 -Dhttps.proxyPort=10991 -DsocksProxyHost=192.168.50.1 -DsocksProxyPort=10991` can not work around. So I create this PR to fix the test bug.
>> 
>> Command wget shows that the machine should connect to internet through a jumper machine(192.168.50.1:10991):
>> 
>>> wget www.bing.com
>> --2025-02-24 17:56:25--  http://www.bing.com/
>> Connecting to 192.168.50.1:10991... connected.
>> Proxy request sent, awaiting response... 301 Moved Permanently
>> Location: http://cn.bing.com/ [following]
>> --2025-02-24 17:56:25--  http://cn.bing.com/
>> Reusing existing connection to 192.168.50.1:10991.
>> Proxy request sent, awaiting response... 200 OK
>> Length: 13006 (13K) [text/html]
>> Saving to: ‘index.html’
>> 
>> 
>> Change has been verified locally, test-fix only and make tests more robustness, no risk.
>
> SendaoYan has updated the pull request incrementally with one additional commit since the last revision:
> 
>   revert change of "255.255.255.0"

I suggest changing the comment that talks about "bugs.openjdk.org". That is one of the addresses at which the site can be reached today, but it might not be tomorrow. Otherwise LGTM. And BTW, the import for SkippedException is probably no longer needed.

test/jdk/java/net/InetAddress/IsReachableViaLoopbackTest.java line 43:

> 41:         try {
> 42:             InetAddress addr = InetAddress.getLoopbackAddress();
> 43:             InetAddress remoteAddr = InetAddress.getByName("23.197.138.208");  //real address of bugs.openjdk.org

Suggestion:

            InetAddress remoteAddr = InetAddress.getByName("23.197.138.208");  // use literal address to avoid DNS checks

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PR Review: https://git.openjdk.org/jdk/pull/23767#pullrequestreview-2657732797
PR Review Comment: https://git.openjdk.org/jdk/pull/23767#discussion_r1979539480