Address PR review feedback for ShareAckMode

- Simplify whats-new.adoc and move detailed migration guide to ref docs
- Remove try-catch around `getConfigurationProperties()` - let it fail if not implemented

Signed-off-by: Soby Chacko <soby.chacko@broadcom.com>

Author: sobychacko

spring-kafka-docs/src/main/antora/modules/ROOT/pages/kafka/kafka-queues.adoc

@@ -524,6 +524,37 @@ Use this mode only when per-record delivery guarantees are not required.
 |Broker auto-ACCEPTs (no recovery)
 |===
 
+[[share-ack-mode-migration]]
+=== Migration from 4.0
+
+In 4.0, share consumer acknowledgment was controlled by `setExplicitShareAcknowledgment(boolean)`.
+In 4.1, this is replaced by `setShareAckMode(ShareAckMode)`.
+The deprecated method still works: `true` maps to `MANUAL`, `false` maps to `EXPLICIT`.
+
+**Default behavior is unchanged.**
+The 4.0 default (`setExplicitShareAcknowledgment(false)`) was container-managed acknowledgment, which is exactly what `ShareAckMode.EXPLICIT` does.
+No action is required for applications using the default.
+
+**If you used `setExplicitShareAcknowledgment(true)`**, replace it:
+
+[source,java]
+----
+// Before (4.0)
+factory.getContainerProperties().setExplicitShareAcknowledgment(true);
+
+// After (4.1)
+factory.getContainerProperties().setShareAckMode(ContainerProperties.ShareAckMode.MANUAL);
+----
+
+**If you set `share.acknowledgement.mode=implicit` in the factory configuration** (via `ConsumerConfig.SHARE_ACKNOWLEDGEMENT_MODE_CONFIG`), note that in 4.0 this setting had no effect because the container always called `consumer.acknowledge()` regardless.
+In 4.1, the container detects this conflict, logs a warning, and overrides the factory setting with explicit mode.
+To use Kafka client implicit mode, set it explicitly on the container:
+
+[source,java]
+----
+factory.getContainerProperties().setShareAckMode(ContainerProperties.ShareAckMode.IMPLICIT);
+----
+
 [[share-acknowledgment-types]]
 === Acknowledgment Types
 

spring-kafka-docs/src/main/antora/modules/ROOT/pages/whats-new.adoc

@@ -17,59 +17,10 @@ See xref:kafka/receiving-messages/listener-annotation.adoc[`@KafkaListener` Anno
 [[x41-share-ack-mode]]
 === Share Consumer Acknowledgment Modes
 
-The boolean `setExplicitShareAcknowledgment(boolean)` property on `ContainerProperties` has been replaced by the `ShareAckMode` enum, which clearly names the three distinct acknowledgment modes:
-
-* `EXPLICIT` (default) — Container-managed.
-The container sends `ACCEPT` after successful processing and delegates error handling to the `ShareConsumerRecordRecoverer` (default: `REJECT`).
-This is the analogue of disabling `auto.commit` on a regular consumer.
-* `MANUAL` — Listener-managed.
-The listener must acknowledge each record via the provided `ShareAcknowledgment`.
-Subsequent polls are blocked until all records from the previous poll are acknowledged.
-* `IMPLICIT` — Kafka client implicit mode.
-The broker auto-accepts all records regardless of processing outcome.
-
-Configure the mode on the factory:
-
-[source,java]
-----
-factory.getContainerProperties().setShareAckMode(ContainerProperties.ShareAckMode.MANUAL);
-----
-
-The deprecated `setExplicitShareAcknowledgment(true)` maps to `MANUAL`; `setExplicitShareAcknowledgment(false)` maps to `EXPLICIT`.
-See xref:kafka/kafka-queues.adoc#share-record-acknowledgment[Record Acknowledgment] for the full reference.
-
-==== Migration Guide
-
-**Default behavior is unchanged.**
-The old `setExplicitShareAcknowledgment(false)` default was already container-managed acknowledgment (the container sent `ACCEPT` on success), which is exactly what `ShareAckMode.EXPLICIT` does.
-No action is required for applications using the default.
-
-**If you used `setExplicitShareAcknowledgment(true)`**, replace it:
-
-[source,java]
-----
-// Before (4.0)
-factory.getContainerProperties().setExplicitShareAcknowledgment(true);
-
-// After (4.1)
-factory.getContainerProperties().setShareAckMode(ContainerProperties.ShareAckMode.MANUAL);
-----
-
-**If you set `share.acknowledgement.mode=implicit` in the factory configuration** (via `ConsumerConfig.SHARE_ACKNOWLEDGEMENT_MODE_CONFIG`), this is a breaking change.
-In 4.0 this setting had no effect because the container always called `consumer.acknowledge()` regardless, which would have thrown `IllegalStateException` in true Kafka implicit mode.
-In 4.1, the container detects this conflict and logs a warning, then overrides the factory setting with explicit mode.
-To genuinely use Kafka client implicit mode — where the broker auto-accepts all records regardless of processing outcome — you must now opt in explicitly:
-
-[source,java]
-----
-factory.getContainerProperties().setShareAckMode(ContainerProperties.ShareAckMode.IMPLICIT);
-----
-
-[WARNING]
-====
-In `ShareAckMode.IMPLICIT`, the `ShareConsumerRecordRecoverer` is not consulted and processing errors do not influence acknowledgment.
-Records are always ACCEPTed by the broker.
-====
+The boolean `setExplicitShareAcknowledgment(boolean)` property on `ContainerProperties` has been replaced by the `ShareAckMode` enum (`EXPLICIT`, `MANUAL`, `IMPLICIT`).
+The deprecated method still works: `true` maps to `MANUAL`, `false` maps to `EXPLICIT`.
+Default behavior is unchanged — applications using the default require no migration.
+See xref:kafka/kafka-queues.adoc#share-record-acknowledgment[Record Acknowledgment] for mode descriptions and xref:kafka/kafka-queues.adoc#share-ack-mode-migration[Migration from 4.0] for upgrade details.
 
 [[x41-share-consumer-error-handling]]
 === Share Consumer Error Handling

spring-kafka/src/main/java/org/springframework/kafka/listener/ShareKafkaMessageListenerContainer.java

@@ -310,7 +310,6 @@ private class ShareListenerConsumer implements Runnable {
 			this.ackTimeoutMs = containerProperties.getShareAcknowledgmentTimeout().toMillis();
 
 			if (shareAckMode == ContainerProperties.ShareAckMode.IMPLICIT) {
-				// Kafka implicit mode: the broker auto-ACCEPTs all records; acknowledge() must not be called.
 				ShareConsumerRecordRecoverer recoverer =
 						ShareKafkaMessageListenerContainer.this.getShareConsumerRecordRecoverer();
 				if (recoverer != ShareConsumerRecordRecoverer.REJECTING) {
@@ -325,20 +324,14 @@ private class ShareListenerConsumer implements Runnable {
 			else {
 				// EXPLICIT and MANUAL both use Kafka client explicit mode so the container
 				// has full per-record acknowledgment control.
-				try {
-					Object configured = ShareKafkaMessageListenerContainer.this.shareConsumerFactory
-							.getConfigurationProperties()
-							.get(ConsumerConfig.SHARE_ACKNOWLEDGEMENT_MODE_CONFIG);
-					if (configured != null && "implicit".equalsIgnoreCase(configured.toString())) {
-						this.logger.warn("Factory configuration has share.acknowledgement.mode=implicit "
-								+ "but ShareAckMode." + shareAckMode + " is active; the container will "
-								+ "override it with explicit mode. To use implicit mode, set "
-								+ "ShareAckMode.IMPLICIT on the container properties instead.");
-					}
-				}
-				catch (UnsupportedOperationException ex) {
-					this.logger.debug(ex, "ShareConsumerFactory does not expose configuration properties; "
-							+ "skipping implicit acknowledgment mode conflict check.");
+				Object configured = ShareKafkaMessageListenerContainer.this.shareConsumerFactory
+						.getConfigurationProperties()
+						.get(ConsumerConfig.SHARE_ACKNOWLEDGEMENT_MODE_CONFIG);
+				if (configured != null && "implicit".equalsIgnoreCase(configured.toString())) {
+					this.logger.warn("Factory configuration has share.acknowledgement.mode=implicit "
+							+ "but ShareAckMode." + shareAckMode + " is active; the container will "
+							+ "override it with explicit mode. To use implicit mode, set "
+							+ "ShareAckMode.IMPLICIT on the container properties instead.");
 				}
 				this.consumer = ShareKafkaMessageListenerContainer.this.shareConsumerFactory.createShareConsumer(
 						ShareKafkaMessageListenerContainer.this.getGroupId(),