Yes, I understood. Flink 2.x is a new major release, there is no guarantee it will support the same connector system versions.
Personally I do not have an idea how much Hive3 is still used with Flink, but taking into account that its EOL and there is a newer version that will be compatible, I do not see any issue with this change. If there is heavy demand, we can consider to go some lengths, but in this particular case I'd say the proper thing to do is just upgrade to Hive4. Let's not carry over tech-debt if it's not a must. Best, Ferenc On Thursday, April 16th, 2026 at 02:59, Lalwani, Jayesh <[email protected]> wrote: > The main issue is that since Flink 2.0 is Java 11+, and Hive 3 doesn't work > beyond Java 8, Flink 2.0+ won't work with Hive 3. Is this something that we > can live with. > > The workaround is a bit hacky. It requires faking the current thread context > class loader to be compatible with Hive 3 > > On 4/14/26, 11:55 AM, "Martijn Visser" <[email protected] > <mailto:[email protected]>> wrote: > > > CAUTION: This email originated from outside of the organization. Do not click > links or open attachments unless you can confirm the sender and know the > content is safe. > > > > > > > Hi Jayesh, > > > Thanks for the message. On your question "Should the Flink Hive connector > work around this for Hive 3.1 users?" the answer is probably "it depends". > Without proper support for newer Java versions, I wouldn't expect this to > work beyond Java 8 to be honest. > > > Best regards, > > > Martijn > > > On Mon, Apr 13, 2026 at 9:08 PM Lalwani, Jayesh <[email protected] > <mailto:[email protected]>> wrote: > > > > Hi devs, > > > > While working on adapting the external Hive connector for Flink 2.0 > > (FLINK-37094), we discovered that the Hive 3.1 profile (-Phive3) is > > broken on Java 9+ due to a bug in Hive's SessionState constructor. > > > > ## Problem > > > > Hive 3.1's SessionState (line 413) casts the system classloader to > > URLClassLoader: > > > > (URLClassLoader) Thread.currentThread().getContextClassLoader() > > > > On Java 9+, the application classloader is > > jdk.internal.loader.ClassLoaders$AppClassLoader, which does not extend > > URLClassLoader. This causes a ClassCastException on any code path that > > initializes SessionState — including HiveParser, HiveDialect, and > > HiveDynamicTableFactory. > > > > Since Flink 2.0 requires Java 11+, this means Hive 3.1 dialect/parser > > features are completely broken on Flink 2.0. > > > > 25 tests fail in the Hive 3.1 profile on Java 11+: > > - HiveDynamicTableFactoryTest (4) > > - HiveTableSourceStatisticsReportTest (8) > > - HiveTableCompactSinkParallelismTest (4) > > - HiveSourceTest (4) > > - HiveDialectSupportSQL11ReservedKeywordAsIdentifierITTest (3) > > - HiveDialectQueryPlanTest (1) > > - HiveFunctionWrapperTest (1) > > > > The Hive 2.3 profile is unaffected. > > > > ## Upstream status > > > > This is a known Hive bug (HIVE-21584 [1]), fixed in Hive 4.0 via > > HIVE-27508 [2]. The fix replaces the URLClassLoader cast with > > SessionState.class.getClassLoader(). Hive 3.1 is EOL and will not > > receive a backport. > > > > ## Reproducing > > > > On the current main branch with Java 11+: > > > > JAVA_HOME=/path/to/java-11 mvn verify \ > > -pl flink-connector-hive -am -Phive3 > > > > ## Question > > > > Should the Flink Hive connector work around this for Hive 3.1 users? > > One approach would be to wrap the thread context classloader in a > > URLClassLoader before calling new SessionState() in HiveSessionState. > > Alternatively, we could document Hive 3.1 as unsupported on Java 11+ > > and recommend users upgrade to Hive 4. > > > > Thoughts? > > > > [1] https://issues.apache.org/jira/browse/HIVE-21584 > > <https://issues.apache.org/jira/browse/HIVE-21584> > > [2] https://issues.apache.org/jira/browse/HIVE-27508 > > <https://issues.apache.org/jira/browse/HIVE-27508> > > > > Best, > > Jayesh > > > > > >
