Current implementation of JVMTI SetExtensionEventCallback() registers the callback but does not enable the event. This behavior matches normal events, so there is a symmetry between normal and extension events.
However, the SetExtensionEventCallback spec states this: Sets the callback function for an extension event and enables the event. Or, if the callback is NULL, disables the event. Note that unlike standard events, setting the callback and enabling the event are a single operation. This wording about enabling/disabling the events has to be removed from SetExtensionEventCallback spec. It seems that extension events are not used by the JVMTI agents. Two extension events are used in number of tests: - `VirtualThreadMount` and `VirtualThreadUnmount` Testing: N/A --------- - [x] I confirm that I make this contribution in accordance with the [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). ------------- Commit messages: - 8394716: SetExtensionEventCallback should not enable the event Changes: https://git.openjdk.org/jdk/pull/33415/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=33415&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8394716 Stats: 8 lines in 1 file changed: 1 ins; 1 del; 6 mod Patch: https://git.openjdk.org/jdk/pull/33415.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/33415/head:pull/33415 PR: https://git.openjdk.org/jdk/pull/33415
