# Kafka Java Client Changelog This changelog lists the client-facing changes in each Apache Kafka® release. The Kafka Java Client ships as part of Apache Kafka® rather than as a separate Confluent artifact, so its version numbers match the Apache Kafka® release they come from. Entries include the `clients`, `consumer`, `producer`, and `admin` components. For changes to brokers, Kafka Streams, or Connect, see the Kafka [full release notes](https://kafka.apache.org/downloads). ## Kafka 4.3.1 Kafka 4.3.1 is a maintenance release. For the complete list of changes across all Kafka components, see the [|ak| 4.3.1 release notes](https://archive.apache.org/dist/kafka/4.3.1/RELEASE_NOTES.html). ### Fixes * [KAFKA-20673](https://issues.apache.org/jira/browse/KAFKA-20673) - AdminClient partition-leader APIs hang when a cached leader has left the cluster. ## Kafka 4.3.0 Kafka 4.3.0 is a feature release. For the complete list of changes across all Kafka components, see the [|ak| 4.3.0 release notes](https://archive.apache.org/dist/kafka/4.3.0/RELEASE_NOTES.html). ### Enhancements * [KAFKA-17019](https://issues.apache.org/jira/browse/KAFKA-17019) - Producer TimeoutException should include root cause. * [KAFKA-18608](https://issues.apache.org/jira/browse/KAFKA-18608) - Enhancing Apache Kafka OAuth2 Authentication: Adding Support for private_key_jwt Client Assertion. * [KAFKA-19833](https://issues.apache.org/jira/browse/KAFKA-19833) - Reduce code duplication in nullable protocol types. * [KAFKA-20065](https://issues.apache.org/jira/browse/KAFKA-20065) - Improve tagging of code examples in javadoc. * [KAFKA-20341](https://issues.apache.org/jira/browse/KAFKA-20341) - Clarify that assignment() and subscription() return a snapshot, not a live view. ### Fixes * [KAFKA-19542](https://issues.apache.org/jira/browse/KAFKA-19542) - Consumer.close() does not remove all added sensors from Metrics. * [KAFKA-19932](https://issues.apache.org/jira/browse/KAFKA-19932) - AdminClient throws TimeoutException when underlying cause is OutOfMemoryError. * [KAFKA-20128](https://issues.apache.org/jira/browse/KAFKA-20128) - TimestampType missing in public API docs. * [KAFKA-20131](https://issues.apache.org/jira/browse/KAFKA-20131) - ClassicKafkaConsumer does not clear endOffsetRequested flag on failed LIST_OFFSETS calls. * [KAFKA-20165](https://issues.apache.org/jira/browse/KAFKA-20165) - Consumer poll may fail with unrecoverable KafkaException if topic not in metadata when fetching committed offsets. * [KAFKA-20183](https://issues.apache.org/jira/browse/KAFKA-20183) - Share consumer group fails when group ID contains colon character. * [KAFKA-20321](https://issues.apache.org/jira/browse/KAFKA-20321) - Mark partitions lost to avoid potential race with buffered records. * [KAFKA-20332](https://issues.apache.org/jira/browse/KAFKA-20332) - Ensure app thread not collecting records for partitions being revoked. * [KAFKA-20382](https://issues.apache.org/jira/browse/KAFKA-20382) - Improve interrupts handling when updating assignment for callbacks. * [KAFKA-20393](https://issues.apache.org/jira/browse/KAFKA-20393) - Kafka client send to wrong IP caused by stickyNode in TelemetrySender. * [KAFKA-20426](https://issues.apache.org/jira/browse/KAFKA-20426) - Using `group.id` and `assign()` causes a busy loop in AsyncKafkaConsumer. * [KAFKA-20428](https://issues.apache.org/jira/browse/KAFKA-20428) - Consumer unsubscribe could fail processing previous assignment change events. ## Kafka 4.2.1 Kafka 4.2.1 is a maintenance release. For the complete list of changes across all Kafka components, see the [|ak| 4.2.1 release notes](https://archive.apache.org/dist/kafka/4.2.1/RELEASE_NOTES.html). ### Fixes * [KAFKA-20131](https://issues.apache.org/jira/browse/KAFKA-20131) - ClassicKafkaConsumer does not clear endOffsetRequested flag on failed LIST_OFFSETS calls. * [KAFKA-20165](https://issues.apache.org/jira/browse/KAFKA-20165) - Consumer poll may fail with unrecoverable KafkaException if topic not in metadata when fetching committed offsets. * [KAFKA-20183](https://issues.apache.org/jira/browse/KAFKA-20183) - Share consumer group fails when group ID contains colon character. * [KAFKA-20332](https://issues.apache.org/jira/browse/KAFKA-20332) - Ensure app thread not collecting records for partitions being revoked. * [KAFKA-20393](https://issues.apache.org/jira/browse/KAFKA-20393) - Kafka client send to wong IP caused by stickyNode in TelemetrySender. ## Kafka 4.2.0 Kafka 4.2.0 is a feature release. For the complete list of changes across all Kafka components, see the [|ak| 4.2.0 release notes](https://archive.apache.org/dist/kafka/4.2.0/RELEASE_NOTES.html). ### Enhancements * [KAFKA-14768](https://issues.apache.org/jira/browse/KAFKA-14768) - Add latency optimization guidance to KafkaProducer.send(). * [KAFKA-19296](https://issues.apache.org/jira/browse/KAFKA-19296) - Revise AsyncKafkaConsumer event wakeup approach. * [KAFKA-19435](https://issues.apache.org/jira/browse/KAFKA-19435) - Optimize `kafka-consumer-groups.sh` to return the offset info of other partitions even when the leader of some partitions are missing. * [KAFKA-19589](https://issues.apache.org/jira/browse/KAFKA-19589) - Check for ability to skip position validation in application thread when collecting buffered data. * [KAFKA-19747](https://issues.apache.org/jira/browse/KAFKA-19747) - Improve handling of failed push telemetry request. * [KAFKA-19820](https://issues.apache.org/jira/browse/KAFKA-19820) - Remove the unnecessary copy from AbstractFetch#fetchablePartitions. * [KAFKA-19822](https://issues.apache.org/jira/browse/KAFKA-19822) - Remove all static classes in Field except TaggedFieldsSection. * [KAFKA-19946](https://issues.apache.org/jira/browse/KAFKA-19946) - Reduce unnecessary work in share session handler. ### Fixes * [KAFKA-12999](https://issues.apache.org/jira/browse/KAFKA-12999) - NPE when accessing RecordHeader.key() concurrently. * [KAFKA-17089](https://issues.apache.org/jira/browse/KAFKA-17089) - Incorrect JWT parsing in OAuthBearerUnsecuredJws. * [KAFKA-17554](https://issues.apache.org/jira/browse/KAFKA-17554) - Flaky testFutureCompletionOutsidePoll in ConsumerNetworkClientTest. * [KAFKA-17725](https://issues.apache.org/jira/browse/KAFKA-17725) - RecordHeader key() is not thread safe. * [KAFKA-18376](https://issues.apache.org/jira/browse/KAFKA-18376) - High CPU load when AsyncKafkaConsumer uses a small max poll value. * [KAFKA-18471](https://issues.apache.org/jira/browse/KAFKA-18471) - Race conditions when accessing RecordHeader data. * [KAFKA-19012](https://issues.apache.org/jira/browse/KAFKA-19012) - Messages ending up on the wrong topic. * [KAFKA-19213](https://issues.apache.org/jira/browse/KAFKA-19213) - Kafka java client ignores default properties. * [KAFKA-19233](https://issues.apache.org/jira/browse/KAFKA-19233) - Members cannot rejoin with epoch=0 for KIP-848. * [KAFKA-19259](https://issues.apache.org/jira/browse/KAFKA-19259) - Async consumer fetch intermittent delays on console consumer. * [KAFKA-19357](https://issues.apache.org/jira/browse/KAFKA-19357) - AsyncConsumer#close hangs during closing because the commitAsync request never completes due to a missing coordinator. * [KAFKA-19394](https://issues.apache.org/jira/browse/KAFKA-19394) - Failure in ConsumerNetworkThread.initializeResources() can cause hangs on AsyncKafkaConsumer.close(). * [KAFKA-19493](https://issues.apache.org/jira/browse/KAFKA-19493) - Incorrect rate metric with larger window size. * [KAFKA-19504](https://issues.apache.org/jira/browse/KAFKA-19504) - AdminClient creates and adds second metrics reporter. * [KAFKA-19564](https://issues.apache.org/jira/browse/KAFKA-19564) - Close Consumer in ConsumerPerformance only after metrics displayed. * [KAFKA-19617](https://issues.apache.org/jira/browse/KAFKA-19617) - ConsumerPerformance#ConsumerPerfRebListener get corrupted value when the number of partitions is increased. * [KAFKA-19722](https://issues.apache.org/jira/browse/KAFKA-19722) - Missing assigned-partitions metric in new consumer. * [KAFKA-19781](https://issues.apache.org/jira/browse/KAFKA-19781) - Consumer NoOffsetForPartitionException for partitions being revoked. * [KAFKA-19813](https://issues.apache.org/jira/browse/KAFKA-19813) - Incorrect jitter value in StreamsGroupHeartbeatRequestManager and AbstractHeartbeatRequestManager. * [KAFKA-20040](https://issues.apache.org/jira/browse/KAFKA-20040) - Race condition on consumer updating positions and unsubscribe when using committed offsets with topic ID. * [KAFKA-20064](https://issues.apache.org/jira/browse/KAFKA-20064) - A race condition in admin client can lead to the result future never being completed. * [KAFKA-7700](https://issues.apache.org/jira/browse/KAFKA-7700) - AbstractConfig does not honor Properties defaults. ## Kafka 4.1.2 Kafka 4.1.2 is a maintenance release. For the complete list of changes across all Kafka components, see the [|ak| 4.1.2 release notes](https://archive.apache.org/dist/kafka/4.1.2/RELEASE_NOTES.html). ### Fixes * [KAFKA-19012](https://issues.apache.org/jira/browse/KAFKA-19012) - Messages ending up on the wrong topic. * [KAFKA-20064](https://issues.apache.org/jira/browse/KAFKA-20064) - A race condition in admin client can lead to the result future never being completed. * [KAFKA-20131](https://issues.apache.org/jira/browse/KAFKA-20131) - ClassicKafkaConsumer does not clear endOffsetRequested flag on failed LIST_OFFSETS calls. ## Kafka 4.1.1 Kafka 4.1.1 is a maintenance release. For the complete list of changes across all Kafka components, see the [|ak| 4.1.1 release notes](https://archive.apache.org/dist/kafka/4.1.1/RELEASE_NOTES.html). ### Enhancements * [KAFKA-19747](https://issues.apache.org/jira/browse/KAFKA-19747) - Improve handling of failed push telemetry request. ### Fixes * [KAFKA-19593](https://issues.apache.org/jira/browse/KAFKA-19593) - Stuck `__consumer_offsets` partition (Kafka Streams app). ## Kafka 4.1.0 Kafka 4.1.0 is a feature release. For the complete list of changes across all Kafka components, see the [|ak| 4.1.0 release notes](https://archive.apache.org/dist/kafka/4.1.0/RELEASE_NOTES.html). ### Enhancements * [KAFKA-10790](https://issues.apache.org/jira/browse/KAFKA-10790) - Detect/Prevent Deadlock on Producer Network Thread. * [KAFKA-15767](https://issues.apache.org/jira/browse/KAFKA-15767) - Refactor TransactionManager to avoid use of ThreadLocal. * [KAFKA-16260](https://issues.apache.org/jira/browse/KAFKA-16260) - Deprecate window.size.ms and window.inner.serde.class in StreamsConfig. * [KAFKA-16758](https://issues.apache.org/jira/browse/KAFKA-16758) - Extend Consumer#close with option to leave the group or not. * [KAFKA-16906](https://issues.apache.org/jira/browse/KAFKA-16906) - Add consistent error handling for Transactions. * [KAFKA-18573](https://issues.apache.org/jira/browse/KAFKA-18573) - Add support for OAuth jwt-bearer grant type. * [KAFKA-18729](https://issues.apache.org/jira/browse/KAFKA-18729) - Improve consumer check for assigned topics from regex. * [KAFKA-18847](https://issues.apache.org/jira/browse/KAFKA-18847) - Refactor OAuth layer to improve reusability. * [KAFKA-18881](https://issues.apache.org/jira/browse/KAFKA-18881) - Document the ConsumerRecord as non-thread safe. * [KAFKA-19002](https://issues.apache.org/jira/browse/KAFKA-19002) - Rewrite ListOffsetsIntegrationTest and move it to clients-integration-test. * [KAFKA-19060](https://issues.apache.org/jira/browse/KAFKA-19060) - Documented null edge cases in the Clients API JavaDoc. * [KAFKA-19152](https://issues.apache.org/jira/browse/KAFKA-19152) - Add top-level documentation for OAuth flows. * [KAFKA-19214](https://issues.apache.org/jira/browse/KAFKA-19214) - Clean up use of Optionals in RequestManagers.entries(). * [KAFKA-19295](https://issues.apache.org/jira/browse/KAFKA-19295) - Remove AsyncKafkaConsumer event ID generation. * [KAFKA-19297](https://issues.apache.org/jira/browse/KAFKA-19297) - Refactor AsyncKafkaConsumer’s use of Java Streams APIs in critical sections. * [KAFKA-8830](https://issues.apache.org/jira/browse/KAFKA-8830) - KIP-512: make Record Headers available in onAcknowledgement. ### Fixes * [KAFKA-12469](https://issues.apache.org/jira/browse/KAFKA-12469) - The topic names in the metrics do not retain their format when extracting through JMX. * [KAFKA-17182](https://issues.apache.org/jira/browse/KAFKA-17182) - Consumer fetch sessions are evicted too quickly with AsyncKafkaConsumer. * [KAFKA-17516](https://issues.apache.org/jira/browse/KAFKA-17516) - Client metrics configuration resources default configs not shown by kafka-configs.sh. * [KAFKA-18117](https://issues.apache.org/jira/browse/KAFKA-18117) - Support topic IDs in consumer SubscriptionState. * [KAFKA-18135](https://issues.apache.org/jira/browse/KAFKA-18135) - ShareConsumer HB UnsupportedVersion msg mixed with Consumer HB. * [KAFKA-18298](https://issues.apache.org/jira/browse/KAFKA-18298) - Fix flaky PlaintextAdminIntegrationTest#testConsumerGroupsDeprecatedConsumerGroupState. * [KAFKA-18400](https://issues.apache.org/jira/browse/KAFKA-18400) - Don’t use YYYY when formatting/parsing dates in Java client. * [KAFKA-19205](https://issues.apache.org/jira/browse/KAFKA-19205) - Inconsistent result of beginningOffsets/endoffset between classic consumer and async consumer with zero timeout. * [KAFKA-19206](https://issues.apache.org/jira/browse/KAFKA-19206) - ConsumerNetworkThread.cleanup() throws NullPointerException if initializeResources() previously failed. * [KAFKA-19242](https://issues.apache.org/jira/browse/KAFKA-19242) - Fix commit bugs caused by race condition during rebalancing. * [KAFKA-19288](https://issues.apache.org/jira/browse/KAFKA-19288) - Ensure new consumer joining attempt not overwritten on delayed HB response to previous leave. * [KAFKA-19300](https://issues.apache.org/jira/browse/KAFKA-19300) - AsyncConsumer#unsubscribe always timeout due to GroupAuthorizationException. * [KAFKA-19351](https://issues.apache.org/jira/browse/KAFKA-19351) - AsyncConsumer#commitAsync should copy the input offsets. * [KAFKA-19356](https://issues.apache.org/jira/browse/KAFKA-19356) - AsyncConsumer should ensure consistency of assigned partitions and subscription. * [KAFKA-19373](https://issues.apache.org/jira/browse/KAFKA-19373) - Fix consumer integration tests checks on protocol name. * [KAFKA-19397](https://issues.apache.org/jira/browse/KAFKA-19397) - TransactionManager.handleCompletedBatch throws NPE. * [KAFKA-19427](https://issues.apache.org/jira/browse/KAFKA-19427) - The \_\_consumer_offsets topic applies the broker configuration message.max.bytes, which may cause the coordinator broker to allocate too much memory and cause OOM. * [KAFKA-19504](https://issues.apache.org/jira/browse/KAFKA-19504) - AdminClient creates and adds second metrics reporter. ## Kafka 4.0.2 Kafka 4.0.2 is a maintenance release. For the complete list of changes across all Kafka components, see the [|ak| 4.0.2 release notes](https://archive.apache.org/dist/kafka/4.0.2/RELEASE_NOTES.html). ### Enhancements * [KAFKA-19747](https://issues.apache.org/jira/browse/KAFKA-19747) - Improve handling of failed push telemetry request. ### Fixes * [KAFKA-19012](https://issues.apache.org/jira/browse/KAFKA-19012) - Messages ending up on the wrong topic. * [KAFKA-20064](https://issues.apache.org/jira/browse/KAFKA-20064) - A race condition in admin client can lead to the result future never being completed. ## Kafka 4.0.1 Kafka 4.0.1 is a maintenance release. For the complete list of changes across all Kafka components, see the [|ak| 4.0.1 release notes](https://archive.apache.org/dist/kafka/4.0.1/RELEASE_NOTES.html). ### Fixes * [KAFKA-19242](https://issues.apache.org/jira/browse/KAFKA-19242) - Fix commit bugs caused by race condition during rebalancing. * [KAFKA-19427](https://issues.apache.org/jira/browse/KAFKA-19427) - The \_\_consumer_offsets topic applies the broker configuration message.max.bytes, which may cause the coordinator broker to allocate too much memory and cause OOM. * [KAFKA-19504](https://issues.apache.org/jira/browse/KAFKA-19504) - AdminClient creates and adds second metrics reporter. ## Kafka 4.0.0 Kafka 4.0.0 is a feature release. For the complete list of changes across all Kafka components, see the [|ak| 4.0.0 release notes](https://archive.apache.org/dist/kafka/4.0.0/RELEASE_NOTES.html). ### Enhancements * [KAFKA-15561](https://issues.apache.org/jira/browse/KAFKA-15561) - Client support for new SubscriptionPattern based subscription. * [KAFKA-16143](https://issues.apache.org/jira/browse/KAFKA-16143) - New JMX metrics for AsyncKafkaConsumer. * [KAFKA-16818](https://issues.apache.org/jira/browse/KAFKA-16818) - Move event processing-related tests from ConsumerNetworkThreadTest to ApplicationEventProcessorTest. * [KAFKA-16899](https://issues.apache.org/jira/browse/KAFKA-16899) - Rename MembershipManagerImpl’s rebalanceTimeoutMs for clarity. * [KAFKA-17137](https://issues.apache.org/jira/browse/KAFKA-17137) - Ensure Admin APIs are properly tested. * [KAFKA-17248](https://issues.apache.org/jira/browse/KAFKA-17248) - Extend KIP-714 to allow for registering additional metrics with clients. * [KAFKA-17340](https://issues.apache.org/jira/browse/KAFKA-17340) - Kafka Java SDK `ConsumerConfig` describe doc is incorrect. * [KAFKA-17377](https://issues.apache.org/jira/browse/KAFKA-17377) - Consider using defaultApiTimeoutMs in AsyncKafkaConsumer#unsubscribe. * [KAFKA-17536](https://issues.apache.org/jira/browse/KAFKA-17536) - Ensure clear error message when “new” consumer used with incompatible cluster. * [KAFKA-17600](https://issues.apache.org/jira/browse/KAFKA-17600) - Add nextOffsets to the ConsumerRecords. * [KAFKA-17663](https://issues.apache.org/jira/browse/KAFKA-17663) - Add Metadata caching in admin.internals.PartitionLeaderStrategy. * [KAFKA-17686](https://issues.apache.org/jira/browse/KAFKA-17686) - AsyncKafkaConsumer.offsetsForTimes() fails with NullPointerException. * [KAFKA-17885](https://issues.apache.org/jira/browse/KAFKA-17885) - Enable clients to rebootstrap based on timeout or error code. * [KAFKA-17927](https://issues.apache.org/jira/browse/KAFKA-17927) - Disallow users to configure `max.in.flight.requests.per.connection` bigger than 5. * [KAFKA-17934](https://issues.apache.org/jira/browse/KAFKA-17934) - Add duration based offset reset option for consumer clients. * [KAFKA-17947](https://issues.apache.org/jira/browse/KAFKA-17947) - Update currentLag(), pause(), and resume() to update SubscriptionState in background thread. * [KAFKA-18046](https://issues.apache.org/jira/browse/KAFKA-18046) - High CPU usage when using Log4j2. * [KAFKA-18071](https://issues.apache.org/jira/browse/KAFKA-18071) - Avoid unneeded background event to refresh regex if no subscription pattern in use. * [KAFKA-18096](https://issues.apache.org/jira/browse/KAFKA-18096) - Allow new consumer to join group after subscribe to pattern if no matching topics. ### Fixes * [KAFKA-16022](https://issues.apache.org/jira/browse/KAFKA-16022) - AsyncKafkaConsumer sometimes complains “No current assignment for partition {}”. * [KAFKA-16248](https://issues.apache.org/jira/browse/KAFKA-16248) - Kafka consumer should cache leader offset ranges. * [KAFKA-16460](https://issues.apache.org/jira/browse/KAFKA-16460) - New consumer times out consuming records in multiple consumer_test.py system tests. * [KAFKA-16576](https://issues.apache.org/jira/browse/KAFKA-16576) - New consumer fails with assert in consumer_test.py’s test_consumer_failure system test. * [KAFKA-16985](https://issues.apache.org/jira/browse/KAFKA-16985) - Ensure consumer attempts to send leave request on close even if interrupted. * [KAFKA-17040](https://issues.apache.org/jira/browse/KAFKA-17040) - Unknown telemetry state: TERMINATED thrown when closing AsyncKafkaConsumer. * [KAFKA-17064](https://issues.apache.org/jira/browse/KAFKA-17064) - New consumer assign should update assignment in background thread. * [KAFKA-17066](https://issues.apache.org/jira/browse/KAFKA-17066) - New consumer updateFetchPositions should perform all operations in background thread. * [KAFKA-17116](https://issues.apache.org/jira/browse/KAFKA-17116) - New consumer may not send effective leave group if member ID received after close. * [KAFKA-17154](https://issues.apache.org/jira/browse/KAFKA-17154) - New consumer subscribe may join group without a call to consumer.poll. * [KAFKA-17182](https://issues.apache.org/jira/browse/KAFKA-17182) - Consumer fetch sessions are evicted too quickly with AsyncKafkaConsumer. * [KAFKA-17201](https://issues.apache.org/jira/browse/KAFKA-17201) - SelectorTest.testInboundConnectionsCountInConnectionCreationMetric leaks sockets and threads. * [KAFKA-17208](https://issues.apache.org/jira/browse/KAFKA-17208) - replica_scale_test.py fails for new consumer. * [KAFKA-17219](https://issues.apache.org/jira/browse/KAFKA-17219) - Adjust system test framework for new protocol consumer. * [KAFKA-17230](https://issues.apache.org/jira/browse/KAFKA-17230) - Kafka consumer client doesn’t report node request-latency metrics. * [KAFKA-17286](https://issues.apache.org/jira/browse/KAFKA-17286) - Flaky PlaintextConsumerSubscriptionTest#testSubscribeInvalidTopic. * [KAFKA-17293](https://issues.apache.org/jira/browse/KAFKA-17293) - New consumer HeartbeatRequestManager should rediscover disconnected coordinator. * [KAFKA-17294](https://issues.apache.org/jira/browse/KAFKA-17294) - Handle retriable errors when fetching offsets in new consumer. * [KAFKA-17295](https://issues.apache.org/jira/browse/KAFKA-17295) - New consumer fails with assert in consumer_test.py’s test_fencing_static_consumer system test. * [KAFKA-17403](https://issues.apache.org/jira/browse/KAFKA-17403) - New consumer may not send leave group on race condition on network thread run & close. * [KAFKA-17439](https://issues.apache.org/jira/browse/KAFKA-17439) - Make polling for new records an explicit action/event in the new consumer. * [KAFKA-17448](https://issues.apache.org/jira/browse/KAFKA-17448) - New consumer seek should update positions in background thread. * [KAFKA-17455](https://issues.apache.org/jira/browse/KAFKA-17455) - `TaskCorruptedException` After Client Quota Throttling. * [KAFKA-17470](https://issues.apache.org/jira/browse/KAFKA-17470) - CommitRequestManager should record failed request only once even if multiple errors in response. * [KAFKA-17478](https://issues.apache.org/jira/browse/KAFKA-17478) - Wrong configuration of metric.reporters lead to NPE in KafkaProducer constructor. * [KAFKA-17480](https://issues.apache.org/jira/browse/KAFKA-17480) - New consumer commit all consumed should retrieve offsets in background thread. * [KAFKA-17505](https://issues.apache.org/jira/browse/KAFKA-17505) - New consumer seekToBeginning/End should run in background thread. * [KAFKA-17518](https://issues.apache.org/jira/browse/KAFKA-17518) - AsyncKafkaConsumer cannot reliably leave group when closed with small timeout. * [KAFKA-17519](https://issues.apache.org/jira/browse/KAFKA-17519) - Define and validate correctness of Consumer.close() and its timeout when thread is interrupted. * [KAFKA-17623](https://issues.apache.org/jira/browse/KAFKA-17623) - Flaky testSeekPositionAndPauseNewlyAssignedPartitionOnPartitionsAssignedCallback. * [KAFKA-17661](https://issues.apache.org/jira/browse/KAFKA-17661) - Fix flaky BufferPoolTest.testBlockTimeout. * [KAFKA-17674](https://issues.apache.org/jira/browse/KAFKA-17674) - New consumer reset positions for newly added partitions before retrieving committed offsets. * [KAFKA-17696](https://issues.apache.org/jira/browse/KAFKA-17696) - New consumer background operations unaware of metadata errors. * [KAFKA-17726](https://issues.apache.org/jira/browse/KAFKA-17726) - New consumer subscribe/subscribeFromPattern in background thread. * [KAFKA-17769](https://issues.apache.org/jira/browse/KAFKA-17769) - Fix flaky PlaintextConsumerSubscriptionTest.testSubscribeInvalidTopicCanUnsubscribe. * [KAFKA-17960](https://issues.apache.org/jira/browse/KAFKA-17960) - PlaintextAdminIntegrationTest.testConsumerGroups fails with CONSUMER group protocol. * [KAFKA-18017](https://issues.apache.org/jira/browse/KAFKA-18017) - New consumer should notify HB errors to group manager after errors have been handled/propagated. * [KAFKA-18034](https://issues.apache.org/jira/browse/KAFKA-18034) - CommitRequestManager should fail pending requests on fatal coordinator errors. * [KAFKA-18040](https://issues.apache.org/jira/browse/KAFKA-18040) - PlaintextProducerSendTest.testSendToPartitionWithFollowerShutdownShouldNotTimeout fails with CONSUMER group protocol. * [KAFKA-18085](https://issues.apache.org/jira/browse/KAFKA-18085) - Abort inflight requests when rebootstrapping due to timeout or error. * [KAFKA-18127](https://issues.apache.org/jira/browse/KAFKA-18127) - Handle subscription pattern used with v0 HB broker. * [KAFKA-18189](https://issues.apache.org/jira/browse/KAFKA-18189) - CoordinatorRequestManager log message can include incorrect coordinator disconnect time. * [KAFKA-18194](https://issues.apache.org/jira/browse/KAFKA-18194) - Flaky test_broker_rolling_bounce due to metadata update. * [KAFKA-18259](https://issues.apache.org/jira/browse/KAFKA-18259) - Documentation for consumer auto.offset.reset contains invalid HTML. * [KAFKA-18469](https://issues.apache.org/jira/browse/KAFKA-18469) - AsyncConsumer fails to retry ListOffsetRequest on ReplicaNotAvailable error without metadata update. * [KAFKA-18569](https://issues.apache.org/jira/browse/KAFKA-18569) - New consumer close may wait on unneeded FindCoordinator. * [KAFKA-18619](https://issues.apache.org/jira/browse/KAFKA-18619) - New consumer topic metadata events should set requireMetadata flag. * [KAFKA-18641](https://issues.apache.org/jira/browse/KAFKA-18641) - AsyncKafkaConsumer could lose records with auto offset commit. * [KAFKA-18645](https://issues.apache.org/jira/browse/KAFKA-18645) - New consumer should align close timeout handling with classic consumer. * [KAFKA-18690](https://issues.apache.org/jira/browse/KAFKA-18690) - New consumer doesn’t updateLatestMetadata for topics matching new regex. * [KAFKA-18784](https://issues.apache.org/jira/browse/KAFKA-18784) - Fix ConsumerWithLegacyMessageFormatIntegrationTest.