RFR: 8327624: Remove VM implementation that bypass verification for core reflection

[Chen Liang]

On Thu, 17 Oct 2024 20:45:53 GMT, Mandy Chung <mchung at openjdk.org> wrote:

> The old core reflection implementation generates dynamic classes that are special cases in the VM to bypass bytecode verification to workaround various issues [1] [2] [3].
> 
> The old core reflection implementation was [removed in JDK 22](https://bugs.openjdk.org/browse/JDK-8305104).   It's time to remove these VM hacks along with the old implementation of  `sun.reflect.ReflectionFactory::newConstructorForSerialization`.   
> 
> After this change, `jdk.internal.reflect.DelegatingClassLoader` no longer exists.   Hence the special metaspace for reflection is no longer needed.  GTests will need to be updated when `Metaspace::ReflectionMetaspaceType` is removed.  Such clean up can be done separately (JDK-8342561).
> 
> [1] [JDK-4486457](https://bugs.openjdk.org/browse/JDK-4486457)
> [2] [JDK-4474172](https://bugs.openjdk.org/browse/JDK-4474172)
> [3] [JDK-6790209](https://bugs.openjdk.org/browse/JDK-6790209)

It seems we can now remove `AccessorGenerator`, `ByteVector*`, `ClassFile*`, `Label`, and `MagicAccessorImpl` Java files from `jdk.internal.reflect`. Do we plan to do that in another RFE?

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PR Comment: https://git.openjdk.org/jdk/pull/21571#issuecomment-2420680392