Bug fixes and improvements for GraalVM for JDK 21.

[fniephaus]

Note: We need to run with --strict-image-heap enabled on GraalVM dev builds / GraalVM for JDK 21 in the future. The current dev build does not have the option, but has --strict-image-heap enabled by default.

[olpaw]

AFAIU we do not want end-users to use the version of NBTs that has this change. This is just for our own testing until time is right to switch to a GraalVM native-image where --strict-image-heap is the default. Correct?

[fniephaus]

AFAIU we do not want end-users to use the version of NBTs that has this change. This is just for our own testing until time is right to switch to a GraalVM native-image where --strict-image-heap is the default. Correct?

We want users of GraalVM for JDK 21 to adopt --strict-image-heap as soon as possible, so support for it in NBT is necessary if you ask me. On the other hand, the additional build-time init policies should still work as before without --strict-image-heap: they are just complementary policies that we didn't know were actually needed. But yes, we should probably test this to be on the safe side.

[fniephaus]

But yes, we should probably test this to be on the safe side.

Here's one way to test this now: f7d1eb6

[olpaw]

But yes, we should probably test this to be on the safe side.

Here's one way to test this now: f7d1eb6

Ok, this proves that the newly added JUnit init-at-build-/run-time configs have no side effect when --strict-image-heap is off.

Sounds safe enough for me.

[fniephaus]

It seems this is blocking the Micronaut Gradle plugin release: micronaut-projects/micronaut-starter#2045 (comment)