(XS) RFR: 8131045: Obsolete JNIDetachReleasesMonitors (original) (raw)

David Holmes david.holmes at oracle.com
Tue Oct 27 05:11:59 UTC 2015

bug: https://bugs.openjdk.java.net/browse/JDK-8131045

webrev: http://cr.openjdk.java.net/~dholmes/8131045/webrev/

The JNIDetachReleasesMonitors flag was added to JDK 6 when it was realized that the VM was not compliant with the JNI specification regarding the release of monitors when a JNI attached thread detached - see JDK-6336479. The flag allowed for restoration of the incorrect behaviour if an application was somehow relying on it.

By now all applications should themselves be JNI-spec compliant and this workaround should not be needed, so we can obsolete the JNIDetachReleasesMonitors flag in JDK 9 (accept it, report it, but take no action) and expire (remove) it in JDK 10.

./b00/linux-i586-internal/images/jdk/bin/java -XX:-JNIDetachReleasesMonitors -version Java HotSpot(TM) Server VM warning: Ignoring option JNIDetachReleasesMonitors; support was removed in 9.0

Testing: JPRT

I haven't yet found any tests that involve this flag but there's bound to be at least one hiding somewhere. :)

A CCC request has been filed.

Thanks, David

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