Integrated: 8290482: Update JNI Specification of DestroyJavaVM for better alignment with JLS, JVMS, and Java SE API Specifications

David Holmes dholmes at openjdk.org
Wed Sep 28 00:01:58 UTC 2022


On Tue, 20 Sep 2022 00:55:32 GMT, David Holmes <dholmes at openjdk.org> wrote:

> This update is primarily about changes to the JNI Invocation API specification, mainly in relation to `DestroyJavaVM`. The motivation for the changes is to align with changes being made to the JLS, JVMS and `java.lang.Runtime`, specifications in relation to VM termination - ref:
> 
> JDK-8290196 12.8: Clarify the definition of program exit
> https://bugs.openjdk.org/browse/JDK-8290196
> 
> JDK-8290388 5.7: Clarify the definition of JVM termination
> https://bugs.openjdk.org/browse/JDK-8290388
> 
> JDK-8290036 Define and specify Runtime shutdown sequence
> https://bugs.openjdk.org/browse/JDK-8290036
> 
> Mostly these are just non-normative changes to the JNI spec prose but there are two actual specification changes:
> 
> 1.  The fact it is an error to detach a thread with active Java frames was only mentioned in the overview section, not in the actual `DetachCurrentThread` specification. (Just an oversight - the VM already checked this)
> 
> 2.  We need to make it an error to call `DestroyJavaVM` from an attached thread with active Java frames (as this can't work for the same reason we disallow `DetachCurrentThread`). This requires an implementation change in Hotspot.
> 
> Issue 2 covers the code change, and regression test, in this PR.
> 
> In addition the specification changes can be seen here:
> 
> - specdiff: http://cr.openjdk.java.net/~dholmes/8290482/8290482-jni-spec/diff.html
> - original: http://cr.openjdk.java.net/~dholmes/8290482/8290482-jni-spec/jni-invocation-original.html
> - new: http://cr.openjdk.java.net/~dholmes/8290482/8290482-jni-spec/jni-invocation-new.html
> 
> The specification itself is not open but comments on the spec changes are welcome - though please see the JBS issue and CSR request first. The revised wording has already been extensively reviewed/negotiated between Alex Buckley, Stuart Marks and myself, so any change must either be a glaring error/problem or else a trivial adjustment.
> 
> Thank you.

This pull request has now been integrated.

Changeset: e5b65c40
Author:    David Holmes <dholmes at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/e5b65c40ea032c6955311593e02ed44f14dfe80a
Stats:     112 lines in 6 files changed: 108 ins; 1 del; 3 mod

8290482: Update JNI Specification of DestroyJavaVM for better alignment with JLS, JVMS, and Java SE API Specifications

Reviewed-by: rehn, coleenp

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PR: https://git.openjdk.org/jdk/pull/10352


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