RFR: 8349910: Implement JEP 517: HTTP/3 for the HTTP Client API [v9]

[Daniel Fuchs]

On Thu, 26 Jun 2025 16:36:40 GMT, Daniel Fuchs <dfuchs at openjdk.org> wrote:

>> Hi,
>> 
>> Please find here a PR for the implementation of [JEP 517: HTTP/3 for the HTTP Client API](https://openjdk.org/jeps/517).
>> 
>> The CSR can be viewed at [JDK-8350588: Implement JEP 517: HTTP/3 for the HTTP Client API](https://bugs.openjdk.org/browse/JDK-8350588)
>> 
>> This JEP proposes to enhance the HttpClient implementation to support HTTP/3.
>> It adds a non-exposed / non-exported internal implementation of the QUIC protocol based on DatagramChannel and the SunJSSE SSLContext provider.
>
> Daniel Fuchs has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 525 commits:
> 
>  - merge latest changes from master branch
>  - http3: run H3StreamLimitReachedTest.java with -Djdk.httpclient.http3.maxStreamLimitTimeout=0 too
>  - retry the ResetControlStream test as needed
>  - http3: fix pending connection and reconnection on stream limit reached logic
>  - http3: pending acknowledgement should be registered before actually sending the packet
>  - http3: fix race with ping requests in PacketSpaceManager.java causing intermittent failures in H3ErrorHandlingTest.java
>  - http3: improve exceptions in Http3ServerExchange.java
>  - http3: fix exception handling in CancelRequestTest.java
>  - http3: review feedback - revert HPACK.java
>  - Implement X509TrustManagerImpl#checkClientTrusted for QUIC
>  - ... and 515 more: https://git.openjdk.org/jdk/compare/5a1301df...0229c215

src/java.base/share/classes/jdk/internal/net/quic/QuicTLSContext.java line 70:

> 68:         if (!(underlyingImpl instanceof SSLContextImpl ssci)) {
> 69:             return false;
> 70:         }

Would there be a way to check the implementation of the X509TrustManager here too? Or can we only do that later on during the handshake?

src/java.base/share/classes/jdk/internal/net/quic/QuicTLSContext.java line 126:

> 124:      *
> 125:      * @param peerHost The peer hostname or IP address. Can be null.
> 126:      * @param peerPort The peer port, can be -1 if the port is unknown

Would that be the hostname in the URI, or in the AltService?
Maybe we could add an `@apiNote` here to clarify it.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24751#discussion_r2169497642
PR Review Comment: https://git.openjdk.org/jdk/pull/24751#discussion_r2169502934