Will the instrumenter detect allocations made via JNI? about allocation-instrumenter

[jhmanson]

Alas, no, it will not. I am aware of a couple of ways of doing this if you are using an OpenJDK-based Java.

First, you can JVMTI's function interception mechanism to intercept JNI's NewObject methods to record the allocation (and then call back to the real NewObject methods). This requires you to write a JVMTI agent in native code. See docs here:

https://docs.oracle.com/en/java/javase/17/docs/specs/jvmti.html#jniIntercept

Alternatively, you can use Hotspot's support for dtrace / systemtap probes. I don't think this is terribly well documented, but I see a page that describes the general idea here:

https://myaut.github.io/dtrace-stap-book/app/java.html

Depending on what you want to do with the information, there may be other ways of accomplishing it. For example, if you are sampling allocations, JVMTI lets you do that.

[jatindersangha]

Hi, thanks for the response.

I think I'll try and build something suitable for my needs using JVMTI.

Thanks,
--Jatinder