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https://issues.apache.org/jira/browse/FLINK-36350?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17883947#comment-17883947
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xuhuang commented on FLINK-36350:
---------------------------------
Hi [~mapohl],
I've identified the cause of the "Illegal Access Error" in JDK 17+.
You are right, it is related to FLINK-29741 and the pull request
[25324|https://github.com/apache/flink/pull/25324].
I have submitted a fix in pull request
[25379|https://github.com/apache/flink/pull/25379].
Here are the details:
According to the [Kryo Object Creation
documentation|https://github.com/EsotericSoftware/kryo?tab=readme-ov-file#instantiatorstrategy],
there are two types of object creation strategies: the
{_}DefaultInstantiatorStrategy{_}, which creates objects using a no-argument
constructor, and the {_}StdInstantiatorStrategy{_}, which utilizes JVM-specific
APIs to create instances without invoking any constructors.
In JDK 17+ [Strong
Encapsulation|https://docs.oracle.com/en/java/javase/17/migrate/migrating-jdk-8-later-jdk-releases.html#GUID-7BB28E4D-99B3-4078-BDC4-FC24180CE82B],
some class reflection issues arise, such as with
{_}org.apache.flink.test.checkpointing.UnalignedCheckpointRescaleITCase$VerifyingSink$State{_}.
In these cases, the {_}DefaultInstantiatorStrategy{_}, which relies on class
constructors, can lead to an IllegalAccessError, while the
_StdInstantiatorStrategy_ does not encounter this issue.
Before pull request [25324|https://github.com/apache/flink/pull/25324], Flink
always used the _StdInstantiatorStrategy_ in both the test and installed
environments, as the _FlinkScalaKryoInstantiator_ was present in the classpath
and utilized the {_}StdInstantiatorStrategy{_}. The detailed logic can be found
in
{_}org.apache.flink.api.java.typeutils.runtime.kryo.KryoSerializer#getKryoInstance{_}.
However, pull request [25324|https://github.com/apache/flink/pull/25324]
removed the _FlinkScalaKryoInstantiator_ class dependency from the flink-test
pom.xml, causing Flink to use the DefaultInstantiatorStrategy in the test
environment, which results in the IllegalAccessError.
Given that the _FlinkScalaKryoInstantiator_ is related to deprecated Scala
APIs, I think it should be removed ultimatly, and we should use the
{_}StdInstantiatorStrategy{_}, as was done previously in Flink.
WDYT?
> IllegalAccessError detected in JDK17+ runs
> ------------------------------------------
>
> Key: FLINK-36350
> URL: https://issues.apache.org/jira/browse/FLINK-36350
> Project: Flink
> Issue Type: Bug
> Components: Tests
> Affects Versions: 2.0-preview
> Reporter: Matthias Pohl
> Priority: Blocker
> Labels: pull-request-available, test-stability
>
> UnalignedCheckpointRescaleITCase and GroupReduceITCase are affected in JDK17
> and JDK21 test profiles.
> https://dev.azure.com/apache-flink/apache-flink/_build/results?buildId=62359&view=logs&j=a596f69e-60d2-5a4b-7d39-dc69e4cdaed3&t=712ade8c-ca16-5b76-3acd-14df33bc1cb1
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