[JDK-8361426] JDK26+ incompatibility because of jdk.internal.ref.Cleaner removal.

[farquet]

The jdk.internal.ref.Cleaner class has now been removed from OpenJDK mainline (JDK26+).

However, Chronicle-Map is using this internal class explicitly here:

Chronicle-Map/src/main/java/net/openhft/chronicle/hash/impl/util/CleanerUtils.java

Line 31 in a59ea09

Class<?> cleanerClass = Class.forName(Jvm.isJava9Plus() ? "jdk.internal.ref.Cleaner" : "sun.misc.Cleaner");

[RichMacDonald]

Can confirm, Chronicle-Map does not run in JDK 26.

[RichMacDonald]

I have a branch that works in JDK 26. And the only pre-26 testing I did was eyeballs (i.e., none). I am sure the developers will have their own way of wanting to implement it, but if anyone needs a quick solution, see:

Forked repository of Chronicler-Core to add an "isJsk26" check:
https://github.com/RichMacDonald/Chronicle-Core

CleanerUtils.java support for JDK26:
https://github.com/RichMacDonald/Chronicle-Map
ea...RichMacDonald:Chronicle-Map:ea

[AlanBateman]

Why is this library hacking into Cleaner internals like this? If there is a strong case for exposing an API then please come to the OpenJDK core-libs-dev mailing to explain the use-case?

[RichMacDonald]

Why is this library hacking into Cleaner internals like this?

You either manage multiple releases for different JDKs or you have one version for everyone. They chose the latter. This is how you write code in JDK 8 for classes that won't exist until JDK 9+.

[AlanBateman]

You either manage multiple releases for different JDKs or you have one version for everyone. They chose the latter. This is how you write code in JDK 8 for classes that won't exist until JDK 9+.

Sure, but what I'm wondering if why this is hacking into jdk.internal.ref.Cleaner on JDK 9+ and why is it hacking into JDK internals in the first place. If there is a compelling use-case for a new API then it would be good to bring it to the OpenJDK core-libs-dev mailing list to discuss.