KAFKA-10525: Emit JSONs with new auto-generated schema (KIP-673) (#9526)

This patch updates the request logger to output request and response payloads in JSON. Payloads are converted to JSON based on their auto-generated schema.

Reviewers:  Lucas Bradstreet <lucas@confluent.io>, David Mao <dmao@confluent.io>, David Jacot <djacot@confluent.io>

clients/src/main/java/org/apache/kafka/clients/NetworkClient.java

@@ -893,10 +893,10 @@ public class NetworkClient implements KafkaClient {
     private void handleApiVersionsResponse(List<ClientResponse> responses,
                                            InFlightRequest req, long now, ApiVersionsResponse apiVersionsResponse) {
         final String node = req.destination;
-        if (apiVersionsResponse.data.errorCode() != Errors.NONE.code()) {
+        if (apiVersionsResponse.data().errorCode() != Errors.NONE.code()) {
-            if (req.request.version() == 0 || apiVersionsResponse.data.errorCode() != Errors.UNSUPPORTED_VERSION.code()) {
+            if (req.request.version() == 0 || apiVersionsResponse.data().errorCode() != Errors.UNSUPPORTED_VERSION.code()) {
                 log.warn("Received error {} from node {} when making an ApiVersionsRequest with correlation id {}. Disconnecting.",
-                        Errors.forCode(apiVersionsResponse.data.errorCode()), node, req.header.correlationId());
+                        Errors.forCode(apiVersionsResponse.data().errorCode()), node, req.header.correlationId());
                 this.selector.close(node);
                 processDisconnection(responses, node, now, ChannelState.LOCAL_CLOSE);
             } else {
@@ -904,8 +904,8 @@ public class NetworkClient implements KafkaClient {
                 // the ApiVersionsRequest when an UNSUPPORTED_VERSION error is returned.
                 // If not provided, the client falls back to version 0.
                 short maxApiVersion = 0;
-                if (apiVersionsResponse.data.apiKeys().size() > 0) {
+                if (apiVersionsResponse.data().apiKeys().size() > 0) {
-                    ApiVersionsResponseKey apiVersion = apiVersionsResponse.data.apiKeys().find(ApiKeys.API_VERSIONS.id);
+                    ApiVersionsResponseKey apiVersion = apiVersionsResponse.data().apiKeys().find(ApiKeys.API_VERSIONS.id);
                     if (apiVersion != null) {
                         maxApiVersion = apiVersion.maxVersion();
                     }
@@ -914,7 +914,7 @@ public class NetworkClient implements KafkaClient {
             }
             return;
         }
-        NodeApiVersions nodeVersionInfo = new NodeApiVersions(apiVersionsResponse.data.apiKeys());
+        NodeApiVersions nodeVersionInfo = new NodeApiVersions(apiVersionsResponse.data().apiKeys());
         apiVersions.update(node, nodeVersionInfo);
         this.connectionStates.ready(node);
         log.debug("Recorded API versions for node {}: {}", node, nodeVersionInfo);

clients/src/main/java/org/apache/kafka/clients/admin/KafkaAdminClient.java

@@ -3451,12 +3451,12 @@ public class KafkaAdminClient extends AdminClient {
                 }
 
                 // If the error is an error at the group level, the future is failed with it
-                final Errors groupError = Errors.forCode(response.data.errorCode());
+                final Errors groupError = Errors.forCode(response.data().errorCode());
                 if (handleGroupRequestError(groupError, context.future()))
                     return;
 
                 final Map<TopicPartition, Errors> partitions = new HashMap<>();
-                response.data.topics().forEach(topic -> topic.partitions().forEach(partition -> partitions.put(
+                response.data().topics().forEach(topic -> topic.partitions().forEach(partition -> partitions.put(
                     new TopicPartition(topic.name(), partition.partitionIndex()),
                     Errors.forCode(partition.errorCode())))
                 );
@@ -4359,10 +4359,10 @@ public class KafkaAdminClient extends AdminClient {
             @Override
             void handleResponse(AbstractResponse response) {
                 final ApiVersionsResponse apiVersionsResponse = (ApiVersionsResponse) response;
-                if (apiVersionsResponse.data.errorCode() == Errors.NONE.code()) {
+                if (apiVersionsResponse.data().errorCode() == Errors.NONE.code()) {
                     future.complete(createFeatureMetadata(apiVersionsResponse));
                 } else {
-                    future.completeExceptionally(Errors.forCode(apiVersionsResponse.data.errorCode()).exception());
+                    future.completeExceptionally(Errors.forCode(apiVersionsResponse.data().errorCode()).exception());
                 }
             }
 

clients/src/main/java/org/apache/kafka/clients/consumer/internals/AbstractCoordinator.java

@@ -732,9 +732,9 @@ public abstract class AbstractCoordinator implements Closeable {
                            RequestFuture<ByteBuffer> future) {
             Errors error = syncResponse.error();
             if (error == Errors.NONE) {
-                if (isProtocolTypeInconsistent(syncResponse.data.protocolType())) {
+                if (isProtocolTypeInconsistent(syncResponse.data().protocolType())) {
                     log.error("SyncGroup failed due to inconsistent Protocol Type, received {} but expected {}",
-                        syncResponse.data.protocolType(), protocolType());
+                        syncResponse.data().protocolType(), protocolType());
                     future.raise(Errors.INCONSISTENT_GROUP_PROTOCOL);
                 } else {
                     log.debug("Received successful SyncGroup response: {}", syncResponse);
@@ -743,7 +743,7 @@ public abstract class AbstractCoordinator implements Closeable {
                     synchronized (AbstractCoordinator.this) {
                         if (!generation.equals(Generation.NO_GENERATION) && state == MemberState.COMPLETING_REBALANCE) {
                             // check protocol name only if the generation is not reset
-                            final String protocolName = syncResponse.data.protocolName();
+                            final String protocolName = syncResponse.data().protocolName();
                             final boolean protocolNameInconsistent = protocolName != null &&
                                 !protocolName.equals(generation.protocolName);
 
@@ -761,7 +761,7 @@ public abstract class AbstractCoordinator implements Closeable {
                                 sensors.successfulRebalanceSensor.record(lastRebalanceEndMs - lastRebalanceStartMs);
                                 lastRebalanceStartMs = -1L;
 
-                                future.complete(ByteBuffer.wrap(syncResponse.data.assignment()));
+                                future.complete(ByteBuffer.wrap(syncResponse.data().assignment()));
                             }
                         } else {
                             log.info("Generation data was cleared by heartbeat thread to {} and state is now {} before " +

clients/src/main/java/org/apache/kafka/clients/producer/internals/TransactionManager.java

@@ -1348,8 +1348,8 @@ public class TransactionManager {
             Errors error = initProducerIdResponse.error();
 
             if (error == Errors.NONE) {
-                ProducerIdAndEpoch producerIdAndEpoch = new ProducerIdAndEpoch(initProducerIdResponse.data.producerId(),
+                ProducerIdAndEpoch producerIdAndEpoch = new ProducerIdAndEpoch(initProducerIdResponse.data().producerId(),
-                        initProducerIdResponse.data.producerEpoch());
+                        initProducerIdResponse.data().producerEpoch());
                 setProducerIdAndEpoch(producerIdAndEpoch);
                 transitionTo(State.READY);
                 lastError = null;
@@ -1623,7 +1623,7 @@ public class TransactionManager {
         @Override
         public void handleResponse(AbstractResponse response) {
             AddOffsetsToTxnResponse addOffsetsToTxnResponse = (AddOffsetsToTxnResponse) response;
-            Errors error = Errors.forCode(addOffsetsToTxnResponse.data.errorCode());
+            Errors error = Errors.forCode(addOffsetsToTxnResponse.data().errorCode());
 
             if (error == Errors.NONE) {
                 log.debug("Successfully added partition for consumer group {} to transaction", builder.data.groupId());

clients/src/main/java/org/apache/kafka/common/requests/AbstractRequest.java

@@ -102,7 +102,7 @@ public abstract class AbstractRequest implements AbstractRequestResponse {
         return SendBuilder.buildRequestSend(header, data());
     }
 
-    protected abstract Message data();
+    public abstract Message data();
 
     // Visible for testing
     public final ByteBuffer serialize() {

clients/src/main/java/org/apache/kafka/common/requests/AddOffsetsToTxnRequest.java

@@ -26,7 +26,7 @@ import java.nio.ByteBuffer;
 
 public class AddOffsetsToTxnRequest extends AbstractRequest {
 
-    public AddOffsetsToTxnRequestData data;
+    private final AddOffsetsToTxnRequestData data;
 
     public static class Builder extends AbstractRequest.Builder<AddOffsetsToTxnRequest> {
         public AddOffsetsToTxnRequestData data;
@@ -53,7 +53,7 @@ public class AddOffsetsToTxnRequest extends AbstractRequest {
     }
 
     @Override
-    protected AddOffsetsToTxnRequestData data() {
+    public AddOffsetsToTxnRequestData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/AddOffsetsToTxnResponse.java

@@ -39,7 +39,7 @@ import java.util.Map;
  */
 public class AddOffsetsToTxnResponse extends AbstractResponse {
 
-    public AddOffsetsToTxnResponseData data;
+    private final AddOffsetsToTxnResponseData data;
 
     public AddOffsetsToTxnResponse(AddOffsetsToTxnResponseData data) {
         super(ApiKeys.ADD_OFFSETS_TO_TXN);
@@ -57,7 +57,7 @@ public class AddOffsetsToTxnResponse extends AbstractResponse {
     }
 
     @Override
-    protected AddOffsetsToTxnResponseData data() {
+    public AddOffsetsToTxnResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/AddPartitionsToTxnRequest.java

@@ -32,7 +32,7 @@ import java.util.Map;
 
 public class AddPartitionsToTxnRequest extends AbstractRequest {
 
-    public final AddPartitionsToTxnRequestData data;
+    private final AddPartitionsToTxnRequestData data;
 
     private List<TopicPartition> cachedPartitions = null;
 
@@ -112,7 +112,7 @@ public class AddPartitionsToTxnRequest extends AbstractRequest {
     }
 
     @Override
-    protected AddPartitionsToTxnRequestData data() {
+    public AddPartitionsToTxnRequestData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/AddPartitionsToTxnResponse.java

@@ -46,7 +46,7 @@ import java.util.Map;
  */
 public class AddPartitionsToTxnResponse extends AbstractResponse {
 
-    public final AddPartitionsToTxnResponseData data;
+    private final AddPartitionsToTxnResponseData data;
 
     private Map<TopicPartition, Errors> cachedErrorsMap = null;
 
@@ -117,7 +117,7 @@ public class AddPartitionsToTxnResponse extends AbstractResponse {
     }
 
     @Override
-    protected AddPartitionsToTxnResponseData data() {
+    public AddPartitionsToTxnResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/AlterClientQuotasRequest.java

@@ -111,7 +111,7 @@ public class AlterClientQuotasRequest extends AbstractRequest {
     }
 
     @Override
-    protected AlterClientQuotasRequestData data() {
+    public AlterClientQuotasRequestData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/AlterClientQuotasResponse.java

@@ -77,7 +77,7 @@ public class AlterClientQuotasResponse extends AbstractResponse {
     }
 
     @Override
-    protected AlterClientQuotasResponseData data() {
+    public AlterClientQuotasResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/AlterConfigsRequest.java

@@ -112,7 +112,7 @@ public class AlterConfigsRequest extends AbstractRequest {
     }
 
     @Override
-    protected AlterConfigsRequestData data() {
+    public AlterConfigsRequestData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/AlterIsrRequest.java

@@ -34,6 +34,7 @@ public class AlterIsrRequest extends AbstractRequest {
         this.data = data;
     }
 
+    @Override
     public AlterIsrRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/AlterIsrResponse.java

@@ -35,6 +35,7 @@ public class AlterIsrResponse extends AbstractResponse {
         this.data = data;
     }
 
+    @Override
     public AlterIsrResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/AlterPartitionReassignmentsResponse.java

@@ -40,6 +40,7 @@ public class AlterPartitionReassignmentsResponse extends AbstractResponse {
             new AlterPartitionReassignmentsResponseData(new ByteBufferAccessor(buffer), version));
     }
 
+    @Override
     public AlterPartitionReassignmentsResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/AlterReplicaLogDirsRequest.java

@@ -61,7 +61,7 @@ public class AlterReplicaLogDirsRequest extends AbstractRequest {
     }
 
     @Override
-    protected AlterReplicaLogDirsRequestData data() {
+    public AlterReplicaLogDirsRequestData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/AlterUserScramCredentialsRequest.java

@@ -59,6 +59,7 @@ public class AlterUserScramCredentialsRequest extends AbstractRequest {
         return new AlterUserScramCredentialsRequest(new AlterUserScramCredentialsRequestData(new ByteBufferAccessor(buffer), version), version);
     }
 
+    @Override
     public AlterUserScramCredentialsRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/AlterUserScramCredentialsResponse.java

@@ -33,6 +33,7 @@ public class AlterUserScramCredentialsResponse extends AbstractResponse {
         this.data = responseData;
     }
 
+    @Override
     public AlterUserScramCredentialsResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/ApiVersionsResponse.java

@@ -46,7 +46,7 @@ public class ApiVersionsResponse extends AbstractResponse {
     public static final ApiVersionsResponse DEFAULT_API_VERSIONS_RESPONSE = createApiVersionsResponse(
             DEFAULT_THROTTLE_TIME, RecordBatch.CURRENT_MAGIC_VALUE);
 
-    public final ApiVersionsResponseData data;
+    private final ApiVersionsResponseData data;
 
     public ApiVersionsResponse(ApiVersionsResponseData data) {
         super(ApiKeys.API_VERSIONS);

clients/src/main/java/org/apache/kafka/common/requests/BeginQuorumEpochRequest.java

@@ -46,7 +46,7 @@ public class BeginQuorumEpochRequest extends AbstractRequest {
         }
     }
 
-    public final BeginQuorumEpochRequestData data;
+    private final BeginQuorumEpochRequestData data;
 
     private BeginQuorumEpochRequest(BeginQuorumEpochRequestData data, short version) {
         super(ApiKeys.BEGIN_QUORUM_EPOCH, version);
@@ -54,7 +54,7 @@ public class BeginQuorumEpochRequest extends AbstractRequest {
     }
 
     @Override
-    protected BeginQuorumEpochRequestData data() {
+    public BeginQuorumEpochRequestData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/BeginQuorumEpochResponse.java

@@ -42,7 +42,7 @@ import java.util.Map;
  * - {@link Errors#UNKNOWN_TOPIC_OR_PARTITION}
  */
 public class BeginQuorumEpochResponse extends AbstractResponse {
-    public final BeginQuorumEpochResponseData data;
+    private final BeginQuorumEpochResponseData data;
 
     public BeginQuorumEpochResponse(BeginQuorumEpochResponseData data) {
         super(ApiKeys.BEGIN_QUORUM_EPOCH);
@@ -86,7 +86,7 @@ public class BeginQuorumEpochResponse extends AbstractResponse {
     }
 
     @Override
-    protected BeginQuorumEpochResponseData data() {
+    public BeginQuorumEpochResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/ControlledShutdownRequest.java

@@ -65,6 +65,7 @@ public class ControlledShutdownRequest extends AbstractRequest {
             version);
     }
 
+    @Override
     public ControlledShutdownRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/ControlledShutdownResponse.java

@@ -62,6 +62,7 @@ public class ControlledShutdownResponse extends AbstractResponse {
         return new ControlledShutdownResponse(new ControlledShutdownResponseData(new ByteBufferAccessor(buffer), version));
     }
 
+    @Override
     public ControlledShutdownResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/CreateAclsRequest.java

@@ -70,7 +70,7 @@ public class CreateAclsRequest extends AbstractRequest {
     }
 
     @Override
-    protected CreateAclsRequestData data() {
+    public CreateAclsRequestData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/CreateAclsResponse.java

@@ -34,7 +34,7 @@ public class CreateAclsResponse extends AbstractResponse {
     }
 
     @Override
-    protected CreateAclsResponseData data() {
+    public CreateAclsResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/CreateDelegationTokenRequest.java

@@ -38,6 +38,7 @@ public class CreateDelegationTokenRequest extends AbstractRequest {
             version);
     }
 
+    @Override
     public CreateDelegationTokenRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/CreateDelegationTokenResponse.java

@@ -64,6 +64,7 @@ public class CreateDelegationTokenResponse extends AbstractResponse {
         return prepareResponse(throttleTimeMs, error, owner, -1, -1, -1, "", ByteBuffer.wrap(new byte[] {}));
     }
 
+    @Override
     public CreateDelegationTokenResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/CreatePartitionsRequest.java

@@ -55,6 +55,7 @@ public class CreatePartitionsRequest extends AbstractRequest {
         this.data = data;
     }
 
+    @Override
     public CreatePartitionsRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/CreatePartitionsResponse.java

@@ -35,6 +35,7 @@ public class CreatePartitionsResponse extends AbstractResponse {
         this.data = data;
     }
 
+    @Override
     public CreatePartitionsResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/CreateTopicsRequest.java

@@ -77,6 +77,7 @@ public class CreateTopicsRequest extends AbstractRequest {
         this.data = data;
     }
 
+    @Override
     public CreateTopicsRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/CreateTopicsResponse.java

@@ -50,6 +50,7 @@ public class CreateTopicsResponse extends AbstractResponse {
         this.data = data;
     }
 
+    @Override
     public CreateTopicsResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/DeleteAclsRequest.java

@@ -100,7 +100,7 @@ public class DeleteAclsRequest extends AbstractRequest {
     }
 
     @Override
-    protected DeleteAclsRequestData data() {
+    public DeleteAclsRequestData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/DeleteAclsResponse.java

@@ -51,7 +51,7 @@ public class DeleteAclsResponse extends AbstractResponse {
     }
 
     @Override
-    protected DeleteAclsResponseData data() {
+    public DeleteAclsResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/DeleteGroupsRequest.java

@@ -46,7 +46,7 @@ public class DeleteGroupsRequest extends AbstractRequest {
         }
     }
 
-    public final DeleteGroupsRequestData data;
+    private final DeleteGroupsRequestData data;
 
     public DeleteGroupsRequest(DeleteGroupsRequestData data, short version) {
         super(ApiKeys.DELETE_GROUPS, version);
@@ -75,7 +75,7 @@ public class DeleteGroupsRequest extends AbstractRequest {
     }
 
     @Override
-    protected DeleteGroupsRequestData data() {
+    public DeleteGroupsRequestData data() {
         return data;
     }
 }

clients/src/main/java/org/apache/kafka/common/requests/DeleteGroupsResponse.java

@@ -39,7 +39,7 @@ import java.util.Map;
  */
 public class DeleteGroupsResponse extends AbstractResponse {
 
-    public final DeleteGroupsResponseData data;
+    private final DeleteGroupsResponseData data;
 
     public DeleteGroupsResponse(DeleteGroupsResponseData data) {
         super(ApiKeys.DELETE_GROUPS);
@@ -47,7 +47,7 @@ public class DeleteGroupsResponse extends AbstractResponse {
     }
 
     @Override
-    protected DeleteGroupsResponseData data() {
+    public DeleteGroupsResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/DeleteRecordsResponse.java

@@ -46,6 +46,7 @@ public class DeleteRecordsResponse extends AbstractResponse {
         this.data = data;
     }
 
+    @Override
     public DeleteRecordsResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/DeleteTopicsRequest.java

@@ -52,6 +52,7 @@ public class DeleteTopicsRequest extends AbstractRequest {
         this.data = data;
     }
 
+    @Override
     public DeleteTopicsRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/DeleteTopicsResponse.java

@@ -38,7 +38,7 @@ public class DeleteTopicsResponse extends AbstractResponse {
      * INVALID_REQUEST(42)
      * TOPIC_DELETION_DISABLED(73)
      */
-    private DeleteTopicsResponseData data;
+    private final DeleteTopicsResponseData data;
 
     public DeleteTopicsResponse(DeleteTopicsResponseData data) {
         super(ApiKeys.DELETE_TOPICS);
@@ -50,6 +50,7 @@ public class DeleteTopicsResponse extends AbstractResponse {
         return data.throttleTimeMs();
     }
 
+    @Override
     public DeleteTopicsResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/DescribeAclsRequest.java

@@ -89,6 +89,7 @@ public class DescribeAclsRequest extends AbstractRequest {
         }
     }
 
+    @Override
     public DescribeAclsRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/DescribeAclsResponse.java

@@ -62,7 +62,7 @@ public class DescribeAclsResponse extends AbstractResponse {
     }
 
     @Override
-    protected DescribeAclsResponseData data() {
+    public DescribeAclsResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/DescribeClientQuotasRequest.java

@@ -106,7 +106,7 @@ public class DescribeClientQuotasRequest extends AbstractRequest {
     }
 
     @Override
-    protected DescribeClientQuotasRequestData data() {
+    public DescribeClientQuotasRequestData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/DescribeClientQuotasResponse.java

@@ -71,7 +71,7 @@ public class DescribeClientQuotasResponse extends AbstractResponse {
     }
 
     @Override
-    protected DescribeClientQuotasResponseData data() {
+    public DescribeClientQuotasResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/DescribeDelegationTokenRequest.java

@@ -60,6 +60,7 @@ public class DescribeDelegationTokenRequest extends AbstractRequest {
         this.data = data;
     }
 
+    @Override
     public DescribeDelegationTokenRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/DescribeDelegationTokenResponse.java

@@ -80,7 +80,7 @@ public class DescribeDelegationTokenResponse extends AbstractResponse {
     }
 
     @Override
-    protected DescribeDelegationTokenResponseData data() {
+    public DescribeDelegationTokenResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/DescribeGroupsRequest.java

@@ -52,6 +52,7 @@ public class DescribeGroupsRequest extends AbstractRequest {
         this.data = data;
     }
 
+    @Override
     public DescribeGroupsRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/DescribeGroupsResponse.java

@@ -44,7 +44,7 @@ public class DescribeGroupsResponse extends AbstractResponse {
      * AUTHORIZATION_FAILED (29)
      */
 
-    private DescribeGroupsResponseData data;
+    private final DescribeGroupsResponseData data;
 
     public DescribeGroupsResponse(DescribeGroupsResponseData data) {
         super(ApiKeys.DESCRIBE_GROUPS);
@@ -105,6 +105,7 @@ public class DescribeGroupsResponse extends AbstractResponse {
         return  groupMetadata;
     }
 
+    @Override
     public DescribeGroupsResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/DescribeLogDirsResponse.java

@@ -39,6 +39,7 @@ public class DescribeLogDirsResponse extends AbstractResponse {
         this.data = data;
     }
 
+    @Override
     public DescribeLogDirsResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/DescribeQuorumRequest.java

@@ -49,7 +49,7 @@ public class DescribeQuorumRequest extends AbstractRequest {
         }
     }
 
-    public final DescribeQuorumRequestData data;
+    private final DescribeQuorumRequestData data;
 
     private DescribeQuorumRequest(DescribeQuorumRequestData data, short version) {
         super(ApiKeys.DESCRIBE_QUORUM, version);
@@ -72,7 +72,7 @@ public class DescribeQuorumRequest extends AbstractRequest {
     }
 
     @Override
-    protected DescribeQuorumRequestData data() {
+    public DescribeQuorumRequestData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/DescribeQuorumResponse.java

@@ -41,7 +41,7 @@ import java.util.Map;
  * - {@link Errors#UNKNOWN_TOPIC_OR_PARTITION}
  */
 public class DescribeQuorumResponse extends AbstractResponse {
-    public final DescribeQuorumResponseData data;
+    private final DescribeQuorumResponseData data;
 
     public DescribeQuorumResponse(DescribeQuorumResponseData data) {
         super(ApiKeys.DESCRIBE_QUORUM);
@@ -63,7 +63,7 @@ public class DescribeQuorumResponse extends AbstractResponse {
     }
 
     @Override
-    protected DescribeQuorumResponseData data() {
+    public DescribeQuorumResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/DescribeUserScramCredentialsRequest.java

@@ -44,7 +44,7 @@ public class DescribeUserScramCredentialsRequest extends AbstractRequest {
         }
     }
 
-    private DescribeUserScramCredentialsRequestData data;
+    private final DescribeUserScramCredentialsRequestData data;
     private final short version;
 
     private DescribeUserScramCredentialsRequest(DescribeUserScramCredentialsRequestData data, short version) {
@@ -58,6 +58,7 @@ public class DescribeUserScramCredentialsRequest extends AbstractRequest {
                 new ByteBufferAccessor(buffer), version), version);
     }
 
+    @Override
     public DescribeUserScramCredentialsRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/DescribeUserScramCredentialsResponse.java

@@ -33,6 +33,7 @@ public class DescribeUserScramCredentialsResponse extends AbstractResponse {
         this.data = responseData;
     }
 
+    @Override
     public DescribeUserScramCredentialsResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/ElectLeadersRequest.java

@@ -90,6 +90,7 @@ public class ElectLeadersRequest extends AbstractRequest {
         this.data = data;
     }
 
+    @Override
     public ElectLeadersRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/ElectLeadersResponse.java

@@ -52,6 +52,7 @@ public class ElectLeadersResponse extends AbstractResponse {
         data.setReplicaElectionResults(electionResults);
     }
 
+    @Override
     public ElectLeadersResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/EndQuorumEpochRequest.java

@@ -47,7 +47,7 @@ public class EndQuorumEpochRequest extends AbstractRequest {
         }
     }
 
-    public final EndQuorumEpochRequestData data;
+    private final EndQuorumEpochRequestData data;
 
     private EndQuorumEpochRequest(EndQuorumEpochRequestData data, short version) {
         super(ApiKeys.END_QUORUM_EPOCH, version);
@@ -55,7 +55,7 @@ public class EndQuorumEpochRequest extends AbstractRequest {
     }
 
     @Override
-    protected EndQuorumEpochRequestData data() {
+    public EndQuorumEpochRequestData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/EndQuorumEpochResponse.java

@@ -42,7 +42,7 @@ import java.util.Map;
  * - {@link Errors#UNKNOWN_TOPIC_OR_PARTITION}
  */
 public class EndQuorumEpochResponse extends AbstractResponse {
-    public final EndQuorumEpochResponseData data;
+    private final EndQuorumEpochResponseData data;
 
     public EndQuorumEpochResponse(EndQuorumEpochResponseData data) {
         super(ApiKeys.END_QUORUM_EPOCH);
@@ -64,7 +64,7 @@ public class EndQuorumEpochResponse extends AbstractResponse {
     }
 
     @Override
-    protected EndQuorumEpochResponseData data() {
+    public EndQuorumEpochResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/EndTxnRequest.java

@@ -26,7 +26,7 @@ import java.nio.ByteBuffer;
 
 public class EndTxnRequest extends AbstractRequest {
 
-    public final EndTxnRequestData data;
+    private final EndTxnRequestData data;
 
     public static class Builder extends AbstractRequest.Builder<EndTxnRequest> {
         public final EndTxnRequestData data;
@@ -60,7 +60,7 @@ public class EndTxnRequest extends AbstractRequest {
     }
 
     @Override
-    protected EndTxnRequestData data() {
+    public EndTxnRequestData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/EndTxnResponse.java

@@ -38,7 +38,7 @@ import java.util.Map;
  */
 public class EndTxnResponse extends AbstractResponse {
 
-    public final EndTxnResponseData data;
+    private final EndTxnResponseData data;
 
     public EndTxnResponse(EndTxnResponseData data) {
         super(ApiKeys.END_TXN);
@@ -61,7 +61,7 @@ public class EndTxnResponse extends AbstractResponse {
     }
 
     @Override
-    protected EndTxnResponseData data() {
+    public EndTxnResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/EnvelopeRequest.java

@@ -80,6 +80,7 @@ public class EnvelopeRequest extends AbstractRequest {
         return new EnvelopeRequest(new EnvelopeRequestData(new ByteBufferAccessor(buffer), version), version);
     }
 
+    @Override
     public EnvelopeRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/EnvelopeResponse.java

@@ -57,6 +57,7 @@ public class EnvelopeResponse extends AbstractResponse {
         return Errors.forCode(data.errorCode());
     }
 
+    @Override
     public EnvelopeResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/ExpireDelegationTokenRequest.java

@@ -39,7 +39,7 @@ public class ExpireDelegationTokenRequest extends AbstractRequest {
     }
 
     @Override
-    protected ExpireDelegationTokenRequestData data() {
+    public ExpireDelegationTokenRequestData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/ExpireDelegationTokenResponse.java

@@ -52,7 +52,7 @@ public class ExpireDelegationTokenResponse extends AbstractResponse {
     }
 
     @Override
-    protected ExpireDelegationTokenResponseData data() {
+    public ExpireDelegationTokenResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/FetchResponse.java

@@ -67,6 +67,7 @@ public class FetchResponse<T extends BaseRecords> extends AbstractResponse {
     private final FetchResponseData data;
     private final LinkedHashMap<TopicPartition, PartitionData<T>> responseDataMap;
 
+    @Override
     public FetchResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/FindCoordinatorRequest.java

@@ -77,6 +77,7 @@ public class FindCoordinatorRequest extends AbstractRequest {
             version);
     }
 
+    @Override
     public FindCoordinatorRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/FindCoordinatorResponse.java

@@ -45,6 +45,7 @@ public class FindCoordinatorResponse extends AbstractResponse {
         this.data = data;
     }
 
+    @Override
     public FindCoordinatorResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/HeartbeatRequest.java

@@ -50,7 +50,7 @@ public class HeartbeatRequest extends AbstractRequest {
         }
     }
 
-    public final HeartbeatRequestData data;
+    private final HeartbeatRequestData data;
 
     private HeartbeatRequest(HeartbeatRequestData data, short version) {
         super(ApiKeys.HEARTBEAT, version);
@@ -72,7 +72,7 @@ public class HeartbeatRequest extends AbstractRequest {
     }
 
     @Override
-    protected HeartbeatRequestData data() {
+    public HeartbeatRequestData data() {
         return data;
     }
 }

clients/src/main/java/org/apache/kafka/common/requests/HeartbeatResponse.java

@@ -58,7 +58,7 @@ public class HeartbeatResponse extends AbstractResponse {
     }
 
     @Override
-    protected HeartbeatResponseData data() {
+    public HeartbeatResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/IncrementalAlterConfigsRequest.java

@@ -91,6 +91,7 @@ public class IncrementalAlterConfigsRequest extends AbstractRequest {
             new ByteBufferAccessor(buffer), version), version);
     }
 
+    @Override
     public IncrementalAlterConfigsRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/IncrementalAlterConfigsResponse.java

@@ -66,6 +66,7 @@ public class IncrementalAlterConfigsResponse extends AbstractResponse {
         this.data = data;
     }
 
+    @Override
     public IncrementalAlterConfigsResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/InitProducerIdRequest.java

@@ -51,7 +51,7 @@ public class InitProducerIdRequest extends AbstractRequest {
         }
     }
 
-    public final InitProducerIdRequestData data;
+    private final InitProducerIdRequestData data;
 
     private InitProducerIdRequest(InitProducerIdRequestData data, short version) {
         super(ApiKeys.INIT_PRODUCER_ID, version);
@@ -73,7 +73,8 @@ public class InitProducerIdRequest extends AbstractRequest {
     }
 
     @Override
-    protected InitProducerIdRequestData data() {
+    public InitProducerIdRequestData data() {
         return data;
     }
+
 }

clients/src/main/java/org/apache/kafka/common/requests/InitProducerIdResponse.java

@@ -36,7 +36,7 @@ import java.util.Map;
  *   - {@link Errors#PRODUCER_FENCED}
  */
 public class InitProducerIdResponse extends AbstractResponse {
-    public final InitProducerIdResponseData data;
+    private final InitProducerIdResponseData data;
 
     public InitProducerIdResponse(InitProducerIdResponseData data) {
         super(ApiKeys.INIT_PRODUCER_ID);
@@ -54,7 +54,7 @@ public class InitProducerIdResponse extends AbstractResponse {
     }
 
     @Override
-    protected InitProducerIdResponseData data() {
+    public InitProducerIdResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/JoinGroupRequest.java

@@ -107,6 +107,7 @@ public class JoinGroupRequest extends AbstractRequest {
         }
     }
 
+    @Override
     public JoinGroupRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/JoinGroupResponse.java

@@ -33,6 +33,7 @@ public class JoinGroupResponse extends AbstractResponse {
         this.data = data;
     }
 
+    @Override
     public JoinGroupResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/LeaderAndIsrRequest.java

@@ -166,7 +166,8 @@ public class LeaderAndIsrRequest extends AbstractControlRequest {
         return Collections.unmodifiableList(data.liveLeaders());
     }
 
-    protected LeaderAndIsrRequestData data() {
+    @Override
+    public LeaderAndIsrRequestData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/LeaderAndIsrResponse.java

@@ -72,7 +72,7 @@ public class LeaderAndIsrResponse extends AbstractResponse {
     }
 
     @Override
-    protected LeaderAndIsrResponseData data() {
+    public LeaderAndIsrResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/LeaveGroupRequest.java

@@ -87,6 +87,7 @@ public class LeaveGroupRequest extends AbstractRequest {
         this.data = data;
     }
 
+    @Override
     public LeaveGroupRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/LeaveGroupResponse.java

@@ -48,7 +48,7 @@ import java.util.Objects;
  */
 public class LeaveGroupResponse extends AbstractResponse {
 
-    public final LeaveGroupResponseData data;
+    private final LeaveGroupResponseData data;
 
     public LeaveGroupResponse(LeaveGroupResponseData data) {
         super(ApiKeys.LEAVE_GROUP);
@@ -122,7 +122,7 @@ public class LeaveGroupResponse extends AbstractResponse {
     }
 
     @Override
-    protected LeaveGroupResponseData data() {
+    public LeaveGroupResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/ListGroupsResponse.java

@@ -33,6 +33,7 @@ public class ListGroupsResponse extends AbstractResponse {
         this.data = data;
     }
 
+    @Override
     public ListGroupsResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/ListPartitionReassignmentsRequest.java

@@ -63,6 +63,7 @@ public class ListPartitionReassignmentsRequest extends AbstractRequest {
             new ByteBufferAccessor(buffer), version), version);
     }
 
+    @Override
     public ListPartitionReassignmentsRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/ListPartitionReassignmentsResponse.java

@@ -38,6 +38,7 @@ public class ListPartitionReassignmentsResponse extends AbstractResponse {
             new ByteBufferAccessor(buffer), version));
     }
 
+    @Override
     public ListPartitionReassignmentsResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/MetadataRequest.java

@@ -108,6 +108,7 @@ public class MetadataRequest extends AbstractRequest {
         this.data = data;
     }
 
+    @Override
     public MetadataRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/MetadataResponse.java

@@ -74,7 +74,7 @@ public class MetadataResponse extends AbstractResponse {
     }
 
     @Override
-    protected MetadataResponseData data() {
+    public MetadataResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/OffsetCommitRequest.java

@@ -73,6 +73,7 @@ public class OffsetCommitRequest extends AbstractRequest {
         this.data = data;
     }
 
+    @Override
     public OffsetCommitRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/OffsetCommitResponse.java

@@ -81,6 +81,7 @@ public class OffsetCommitResponse extends AbstractResponse {
         this(DEFAULT_THROTTLE_TIME, responseData);
     }
 
+    @Override
     public OffsetCommitResponseData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/OffsetDeleteRequest.java

@@ -46,7 +46,7 @@ public class OffsetDeleteRequest extends AbstractRequest {
         }
     }
 
-    public final OffsetDeleteRequestData data;
+    private final OffsetDeleteRequestData data;
 
     public OffsetDeleteRequest(OffsetDeleteRequestData data, short version) {
         super(ApiKeys.OFFSET_DELETE, version);
@@ -71,7 +71,7 @@ public class OffsetDeleteRequest extends AbstractRequest {
     }
 
     @Override
-    protected OffsetDeleteRequestData data() {
+    public OffsetDeleteRequestData data() {
         return data;
     }
 }

clients/src/main/java/org/apache/kafka/common/requests/OffsetDeleteResponse.java

@@ -44,7 +44,7 @@ import java.util.Map;
  */
 public class OffsetDeleteResponse extends AbstractResponse {
 
-    public final OffsetDeleteResponseData data;
+    private final OffsetDeleteResponseData data;
 
     public OffsetDeleteResponse(OffsetDeleteResponseData data) {
         super(ApiKeys.OFFSET_DELETE);
@@ -52,7 +52,7 @@ public class OffsetDeleteResponse extends AbstractResponse {
     }
 
     @Override
-    protected OffsetDeleteResponseData data() {
+    public OffsetDeleteResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/OffsetFetchRequest.java

@@ -38,7 +38,7 @@ public class OffsetFetchRequest extends AbstractRequest {
     private static final Logger log = LoggerFactory.getLogger(OffsetFetchRequest.class);
 
     private static final List<OffsetFetchRequestTopic> ALL_TOPIC_PARTITIONS = null;
-    public final OffsetFetchRequestData data;
+    private final OffsetFetchRequestData data;
 
     public static class Builder extends AbstractRequest.Builder<OffsetFetchRequest> {
 
@@ -175,7 +175,7 @@ public class OffsetFetchRequest extends AbstractRequest {
     }
 
     @Override
-    protected OffsetFetchRequestData data() {
+    public OffsetFetchRequestData data() {
         return data;
     }
 }

clients/src/main/java/org/apache/kafka/common/requests/OffsetFetchResponse.java

@@ -63,7 +63,7 @@ public class OffsetFetchResponse extends AbstractResponse {
     private static final List<Errors> PARTITION_ERRORS = Arrays.asList(
         Errors.UNKNOWN_TOPIC_OR_PARTITION, Errors.TOPIC_AUTHORIZATION_FAILED);
 
-    public final OffsetFetchResponseData data;
+    private final OffsetFetchResponseData data;
     private final Errors error;
 
     public static final class PartitionData {
@@ -219,7 +219,7 @@ public class OffsetFetchResponse extends AbstractResponse {
     }
 
     @Override
-    protected OffsetFetchResponseData data() {
+    public OffsetFetchResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/ProduceResponse.java

@@ -107,6 +107,7 @@ public class ProduceResponse extends AbstractResponse {
         return data;
     }
 
+    @Override
     public ProduceResponseData data() {
         return this.data;
     }

clients/src/main/java/org/apache/kafka/common/requests/RenewDelegationTokenRequest.java

@@ -38,6 +38,7 @@ public class RenewDelegationTokenRequest extends AbstractRequest {
             new ByteBufferAccessor(buffer), version), version);
     }
 
+    @Override
     public RenewDelegationTokenRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/RenewDelegationTokenResponse.java

@@ -44,7 +44,7 @@ public class RenewDelegationTokenResponse extends AbstractResponse {
     }
 
     @Override
-    protected RenewDelegationTokenResponseData data() {
+    public RenewDelegationTokenResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/SaslAuthenticateRequest.java

@@ -60,6 +60,7 @@ public class SaslAuthenticateRequest extends AbstractRequest {
         this.data = data;
     }
 
+    @Override
     public SaslAuthenticateRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/SaslAuthenticateResponse.java

@@ -68,7 +68,7 @@ public class SaslAuthenticateResponse extends AbstractResponse {
     }
 
     @Override
-    protected SaslAuthenticateResponseData data() {
+    public SaslAuthenticateResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/SaslHandshakeRequest.java

@@ -61,6 +61,7 @@ public class SaslHandshakeRequest extends AbstractRequest {
         this.data = data;
     }
 
+    @Override
     public SaslHandshakeRequestData data() {
         return data;
     }

clients/src/main/java/org/apache/kafka/common/requests/SaslHandshakeResponse.java

@@ -58,7 +58,7 @@ public class SaslHandshakeResponse extends AbstractResponse {
     }
 
     @Override
-    protected SaslHandshakeResponseData data() {
+    public SaslHandshakeResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/StopReplicaRequest.java

@@ -211,7 +211,7 @@ public class StopReplicaRequest extends AbstractControlRequest {
     }
 
     @Override
-    protected StopReplicaRequestData data() {
+    public StopReplicaRequestData data() {
         return data;
     }
 }

clients/src/main/java/org/apache/kafka/common/requests/StopReplicaResponse.java

@@ -71,7 +71,7 @@ public class StopReplicaResponse extends AbstractResponse {
     }
 
     @Override
-    protected StopReplicaResponseData data() {
+    public StopReplicaResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/SyncGroupRequest.java

@@ -53,7 +53,7 @@ public class SyncGroupRequest extends AbstractRequest {
         }
     }
 
-    public final SyncGroupRequestData data;
+    private final SyncGroupRequestData data;
 
     public SyncGroupRequest(SyncGroupRequestData data, short version) {
         super(ApiKeys.SYNC_GROUP, version);
@@ -92,7 +92,7 @@ public class SyncGroupRequest extends AbstractRequest {
     }
 
     @Override
-    protected SyncGroupRequestData data() {
+    public SyncGroupRequestData data() {
         return data;
     }
 }

clients/src/main/java/org/apache/kafka/common/requests/SyncGroupResponse.java

@@ -26,7 +26,7 @@ import java.util.Map;
 
 public class SyncGroupResponse extends AbstractResponse {
 
-    public final SyncGroupResponseData data;
+    private final SyncGroupResponseData data;
 
     public SyncGroupResponse(SyncGroupResponseData data) {
         super(ApiKeys.SYNC_GROUP);
@@ -48,7 +48,7 @@ public class SyncGroupResponse extends AbstractResponse {
     }
 
     @Override
-    protected SyncGroupResponseData data() {
+    public SyncGroupResponseData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/TxnOffsetCommitRequest.java

@@ -44,7 +44,7 @@ public class TxnOffsetCommitRequest extends AbstractRequest {
 
     private static final Logger log = LoggerFactory.getLogger(TxnOffsetCommitRequest.class);
 
-    public final TxnOffsetCommitRequestData data;
+    private final TxnOffsetCommitRequestData data;
 
     public static class Builder extends AbstractRequest.Builder<TxnOffsetCommitRequest> {
 
@@ -168,7 +168,7 @@ public class TxnOffsetCommitRequest extends AbstractRequest {
     }
 
     @Override
-    protected TxnOffsetCommitRequestData data() {
+    public TxnOffsetCommitRequestData data() {
         return data;
     }
 

clients/src/main/java/org/apache/kafka/common/requests/TxnOffsetCommitResponse.java

@@ -47,7 +47,7 @@ import java.util.Map;
  */
 public class TxnOffsetCommitResponse extends AbstractResponse {
 
-    public final TxnOffsetCommitResponseData data;
+    private final TxnOffsetCommitResponseData data;
 
     public TxnOffsetCommitResponse(TxnOffsetCommitResponseData data) {
         super(ApiKeys.TXN_OFFSET_COMMIT);
@@ -78,7 +78,7 @@ public class TxnOffsetCommitResponse extends AbstractResponse {
     }
 
     @Override
-    protected TxnOffsetCommitResponseData data() {
+    public TxnOffsetCommitResponseData data() {
         return data;
     }