RFR: 8376031: HttpsURLConnection.getServerCertificates() throws "java.lang.IllegalStateException: connection not yet open" for the HEAD method [v3]

[Jaikiran Pai]

On Tue, 3 Feb 2026 18:24:48 GMT, Daniel Fuchs <dfuchs at openjdk.org> wrote:

>> The issue here is that `HttpURLConnection` is automatically disconnected (`HttpClient` is set to `null`, `connected` is set to `false`) when a response with no response body bytes is received. This happens before a fake empty body input stream is returned to the user. That behaviour also occurs with any method for which `content-length: 0` is returned (GET, POST, custom, anything), and with any status code (204, 304) for which there is no body.
>> 
>> In this case, the proposed fix is to store the `SSLSession` in the `AbstractDelegateHttpsURLConnection` subclass until such a time where `disconnect()` is explicitely closed. Information pertaining to SSL, such as server certificates, can be extracted from the saved `SSLSession`.
>
> Daniel Fuchs has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:
> 
>  - Review feedback: improve the test to verify that certificates are returned
>  - Merge branch 'master' into https_certs_8376031
>  - Review feedback
>  - 8376031: HttpsURLConnection.getServerCertificates() throws "java.lang.IllegalStateException: connection not yet open" for the HEAD method

Thank you Daniel for these updates. This looks good to me.

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Marked as reviewed by jpai (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/29489#pullrequestreview-3748395082