Since I was looking into this I can put my 5 cents here
1. Do you need all modules up and running with jdk25 or just some of them?
Asking since some of them like e.g. all modules under flink-table
are able to be compiled and pass tests with jdk25 (starting Flink
2.2.0)
Also if you do not use hadoop or anything which brings hadoop with
transitive dependencies it actually already works with jdk25
2. The main problem is as mentioned above is Removal of Security
Manager which happened in jdk 24 [1]
2.1 All (or most of) hadoop issues are just a sequence of Security
Manager permanent disablement.
In Hadoop it was partially mitigated in subtasks of HADOOP-19486[2].
So first it requires bumping of hadoop version in Flink.
Second it requires a bump of all other dependencies
requiring an old hadoop version (like parquet/orc/etc)
2.2 Also there is FlinkSecurityManager[3] which is trying to
intercept some System.exit calls
Need to do something with this as well.
[1] https://openjdk.org/jeps/486
[2] https://issues.apache.org/jira/browse/HADOOP-19486
[3]
https://github.com/apache/flink/blob/master/flink-core/src/main/java/org/apache/flink/core/security/FlinkSecurityManager.java
On Wed, May 20, 2026 at 4:21 PM Martijn Visser <[email protected]> wrote:
>
> Hi Dan,
>
> I think would be helpful if someone with the right expertise can help
> the community with supporting Java 25. I haven't seen any activity on
> the Dev mailing list on this subject, and also not a FLIP on how to
> add support for it (if needed), so I doubt that there's anyone really
> actively working on it at this moment.
>
> Best regards,
>
> Martijn
>
> Op di 19 mei 2026 om 15:23 schreef Daniel Burrell via user
> <[email protected]>:
> >
> > Hi all,
> >
> > I'd like to start a discussion about Java 25 support for Flink, as
> > suggested by David Anderson on the community Slack channel:
> > https://apache-flink.slack.com/archives/C03GV7L3G2C/p1778180123814119?thread_ts=1778141099.814779&cid=C03GV7L3G2C.
> >
> > Java 25 has been GA for approximately 9 months now, and FLINK-37719 tracks
> > several open subtasks required for compatibility. I noticed some of those
> > subtasks have stalled — for example, the Security Manager removal PR was
> > closed pending a mailing list discussion that doesn't appear to have
> > happened yet.
> >
> > This is becoming a significant blocker for us. We run a monorepo, which
> > means Flink is currently the sole dependency preventing our entire codebase
> > from adopting Java 25. We can't afford to hold back our wider systems from
> > Java 25's performance optimizations and language improvements for an
> > extended period. We previously experienced a painful lag between Java 17
> > and 21 support in Flink, and we're keen to avoid a repeat of that
> > situation, but this will be the third time our codebase has been stalled
> > due to flink support of current Java languages.
> >
> > We understand this didn't make the 2.3 feature freeze. Could the community
> > consider targeting Java 25 support for 2.4? Specifically, it would be
> > helpful to understand:
> >
> > 1. Are there any fundamental technical blockers beyond the subtasks
> > listed in FLINK-37719?
> > 2. Is anyone actively working on or planning to pick up the remaining
> > items?
> > 3. What can downstream users like us do to help move this forward —
> > testing, reviews, or contributing patches?
> >
> > We'd strongly prefer to wait for upstream support rather than pursue
> > alternatives, but we do need some visibility into a realistic timeline so
> > we can plan accordingly.
> >
> > Kind regards
> >
> >
> > Dan B
> >
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Best regards,
Sergey
