[FIXED] Does OpenJDK 11 support Java Flight Recorder?

Issue

Following this post :

jfr is supported natively in openjdk 11

and it is confirmed by the features list of OpenJDK 11:

328: Flight Recorder

However, from this DZone article, about using JFR-linked option -XX:+UnlockCommercialFeatures:

OpenJDK doesn’t recognize this option

And when I try for ex. with Gradle: ./gradlew clean -Dorg.gradle.jvmargs="-XX:+UnlockCommercialFeatures" I get

Process command line: C:\Program Files\AdoptOpenJDK\jdk-11.0.11.9-hotspot\bin\java.exe -XX:+UnlockCommercialFeatures (...)

Unrecognized VM option 'UnlockCommercialFeatures'

What am I missing here ?

Solution

JFR was a commercial feature in Oracle Java up to Java 1.8 that needed to be specially enabled (using -XX:+UnlockCommercialFeatures).

With Java 11 and later it is no longer a commercial feature so you don't need this flag.

Actually the linked article states:

JFR Packaging Differences
Oracle JDK 11 emits a warning when using the -XX:+UnlockCommercialFeatures option, whereas OpenJDK doesn’t recognize this option and reports an error.

And the example below that the author shows doesn't use the -XX:+UnlockCommercialFeatures.

Answered By - Thomas Kläger