On Fri, 28 Aug 2026 19:30:27 GMT, Weijun Wang <[email protected]> wrote:

> The enhancement implements the new RFC 9846-style support group selection on 
> the server side (first mutual group matters) and change the supported-groups 
> format. Specifically:
> 
> 1. `SSLParameters.setNamedGroups` and the `jdk.tls.namedGroups` system 
> property now recognize a *-prefix on a group name.
> 2. The prefix does not change the supported_groups extension.
> 3. On a TLS 1.3 client, usable starred groups determine the initial key_share 
> entries. If no usable starred group remains, JSSE falls back to its existing 
> automatic key-share selection.
> 4. SunJSSE’s default parameters contains 2 starred groups, which can be 
> observed by `getNamedGroups`.
> 5. The server ignores the marker in its own configuration.
> 6. Server group selection now follows RFC 9846: choose the first mutually 
> supported group according to the client’s supported_groups order, then sends 
> ServerHello if its key share is present or HelloRetryRequest if not.
> 
> No new API or system property defined for the new format. The existing 
> methods and system property are already called a lot by both JSSE itself and 
> an application. The default value of the system property is empty which gives 
> each provider the chance to define it itself.
> 
> ---------
> - [x] I confirm that I make this contribution in accordance with the [OpenJDK 
> Interim AI Policy](https://openjdk.org/legal/ai).

src/java.base/share/classes/javax/net/ssl/SSLParameters.java line 926:

> 924:      * of the names have the prefix or these names are not available, the
> 925:      * implementation determines which key shares to include in the 
> message.
> 926:      * The prefix is ignored on the server side.

Maybe we should described this as a hint, since it's implementation-dependent.

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PR Review Comment: https://git.openjdk.org/jdk/pull/32586#discussion_r4008087750

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