Proposal for back-porting JFR to OpenJDK8u

Andrew Hughes gnu.andrew at
Thu Dec 6 18:30:34 UTC 2018

On Thu, 6 Dec 2018 at 14:55, Gil Tene <gil at> wrote:


> [By my reading] To remain compatible/compliant with a Java Specification
> (Java SE 8 in this case), you cannot “modify, subset, superset, or otherwise
> extend the java.*, java.*, com.sun.*, and* namespaces.
> The jdk.* namespace is fair game from a spec compatibility perspective,
> regardless of whether or not the classes end up in rt.jar. (I too like the
> idea of a separate jar).

For what it's worth, com.sun.* (and presumably its successor,*)
seem to be fair game as well, as it's being used in other backports. This
includes cases like getting Nimbus into OpenJDK 6, where public API needed to be
downgraded to private.

If the result passes the TCK, we should be good on this.
Andrew :)

Senior Free Java Software Engineer
Red Hat, Inc. (

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