RFR: 8377796: java.net.http.HttpClient.send() and sendAsync() never complete when BodyHandler.apply() returns null [v4]

[Volkan Yazici]

On Thu, 12 Feb 2026 14:40:35 GMT, Volkan Yazici <vyazici at openjdk.org> wrote:

>> Jaikiran Pai has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   undo unintentional whitespace changes during merge conflict resolution
>
> test/jdk/java/net/httpclient/NullReturningBodyHandlerTest.java line 175:
> 
>> 173:                 .build();
>> 174:         // test for HTTP/2 upgrade when there are no already established connections
>> 175:         args.add(Arguments.of(new Request(h2HttpReq, Version.HTTP_2)));
> 
> `test()` issues two requests one after another using `send()` and `sendAsync()`. Effectively, `sendAsync()` will never observe an empty connection pool. I don't think this is something bad, but it makes me think if we add any value by trying with an empty connection pool.

I see that there is a probability that `BodyHandler::apply` returning null will fail the HTTP/2 upgrade, and no connections will make it to the pool. Hence, both `send()` and `sendAsync()` will observe an empty pool.

> test/jdk/java/net/httpclient/NullReturningBodyHandlerTest.java line 177:
> 
>> 175:         args.add(Arguments.of(new Request(h2HttpReq, Version.HTTP_2)));
>> 176:         // test for HTTP/2 upgrade when there is an established connection
>> 177:         args.add(Arguments.of(new Request(h2HttpReq, Version.HTTP_2, true)));
> 
> The test case added 1 line above will already admit a HTTP/2 clear-text connection to the pool. Why do we need `requiresWarmupHEADRequest=true` here?

I see that there is a probability that `BodyHandler::apply` returning null will fail the HTTP/2 upgrade, and no connections will make it to the pool. Hence, a 2nd `args` entry with explicit `requiresWarmupHEADRequest=true` makes sense.

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PR Review Comment: https://git.openjdk.org/jdk/pull/29691#discussion_r2812203064
PR Review Comment: https://git.openjdk.org/jdk/pull/29691#discussion_r2812199370