RFR: 8329829: HttpClient: Add a BodyPublishers.ofFileChannel method [v4]

[Jaikiran Pai]

On Wed, 30 Jul 2025 09:33:29 GMT, Volkan Yazici <vyazici at openjdk.org> wrote:

>> test/jdk/java/net/httpclient/FileChannelPublisherTest.java line 513:
>> 
>>> 511:             LOGGER.log("Verifying the client failure");
>>> 512:             Exception requestFailure = assertThrows(ExecutionException.class, () -> responseFutureRef.get().get());
>>> 513:             assertInstanceOf(UncheckedIOException.class, requestFailure.getCause());
>> 
>> I think the application should be receiving a `IOException` (both for send() and sendAsync()) instead of a `UncheckedIOException`.
>
> The `IOE` thrown is wrapped by an `UncheckedIOE` in `FileChannelIterator::next`, which overrides `Iterator::next` and that does not allow a `throws` in the `next()` footprint. Would you mind elaborating on your remark, please?

Hello Volkan, the specification of `HttpClient.send(...)` (and sendAsync()) is that it throws a checked `IOException`. So any other exceptions that we throw internally (like this one) need to be converted to an `IOException` when it reaches the application code.

We have code in `HttpClientImpl.send(...)` which currently does instanceof checks against these exceptions and converts them to an `IOException`. I'm guessing your test is currently passing, which suggests to me that `sendAsync()` is propagating a `UncheckedIOException` to the application code. Would it be possible to tweak the test a bit to replace that call of `sendAsync()` with a `send()` (even if those tweaked changes cannot be pushed to this PR) and see what gets propagated? I suspect it would be `IOException`.

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

PR Review Comment: https://git.openjdk.org/jdk/pull/26155#discussion_r2242150036