diff --git a/java-client/src/main/java/org/opensearch/client/transport/aws/AwsSdk2Transport.java b/java-client/src/main/java/org/opensearch/client/transport/aws/AwsSdk2Transport.java
index c56723055..94e0d3ba4 100644
--- a/java-client/src/main/java/org/opensearch/client/transport/aws/AwsSdk2Transport.java
+++ b/java-client/src/main/java/org/opensearch/client/transport/aws/AwsSdk2Transport.java
@@ -38,6 +38,7 @@
 import software.amazon.awssdk.http.async.AsyncExecuteRequest;
 import software.amazon.awssdk.http.async.SdkAsyncHttpClient;
 import software.amazon.awssdk.regions.Region;
+import software.amazon.awssdk.utils.SdkAutoCloseable;
 
 import javax.annotation.CheckForNull;
 import javax.annotation.Nonnull;
@@ -70,8 +71,7 @@ public class AwsSdk2Transport implements OpenSearchTransport {
     public static final Integer DEFAULT_REQUEST_COMPRESSION_SIZE = 8192;
 
     private static final byte[] NO_BYTES = new byte[0];
-    private final SdkHttpClient httpClient;
-    private final SdkAsyncHttpClient asyncHttpClient;
+    private final SdkAutoCloseable httpClient;
     private final String host;
     private final String signingServiceName;
     private final Region signingRegion;
@@ -79,12 +79,12 @@ public class AwsSdk2Transport implements OpenSearchTransport {
     private final AwsSdk2TransportOptions transportOptions;
 
     /**
-     * Create an {@link OpenSearchTransport} with a synchronous AWS HTTP client.
+     * Create an {@link OpenSearchTransport} with an asynchronous AWS HTTP client.
      * <p>
      * Note that asynchronous OpenSearch requests sent through this transport will be dispatched
      * *synchronously* on the calling thread.
      *
-     * @param httpClient HTTP client to use for OpenSearch requests.
+     * @param asyncHttpClient Asynchronous HTTP client to use for OpenSearch requests.
      * @param host The fully qualified domain name to connect to.
      * @param signingRegion The AWS region for which requests will be signed. This should typically match the region in `host`.
      * @param options Options that apply to all requests. Can be null. Create with
@@ -92,132 +92,82 @@ public class AwsSdk2Transport implements OpenSearchTransport {
      *                compression options, etc.
      */
     public AwsSdk2Transport(
-            @Nonnull SdkHttpClient httpClient,
+            @CheckForNull SdkAsyncHttpClient asyncHttpClient,
             @Nonnull String host,
             @Nonnull Region signingRegion,
             @CheckForNull AwsSdk2TransportOptions options) {
-        this(httpClient, null, host, "es", signingRegion, options);
+        this(asyncHttpClient, host, "es", signingRegion, options);
     }
 
     /**
      * Create an {@link OpenSearchTransport} with a synchronous AWS HTTP client.
-     * <p>
-     * Note that asynchronous OpenSearch requests sent through this transport will be dispatched
-     * *synchronously* on the calling thread.
      *
-     * @param httpClient HTTP client to use for OpenSearch requests.
+     * @param syncHttpClient Synchronous HTTP client to use for OpenSearch requests.
      * @param host The fully qualified domain name to connect to.
-     * @param signingServiceName The AWS signing service name, one of `es` (Amazon OpenSearch) or `aoss` (Amazon OpenSearch Serverless).
      * @param signingRegion The AWS region for which requests will be signed. This should typically match the region in `host`.
      * @param options Options that apply to all requests. Can be null. Create with
      *                {@link AwsSdk2TransportOptions#builder()} and use these to specify non-default credentials,
      *                compression options, etc.
      */
     public AwsSdk2Transport(
-            @Nonnull SdkHttpClient httpClient,
+            @CheckForNull SdkHttpClient syncHttpClient,
             @Nonnull String host,
-            @Nonnull String signingServiceName,
             @Nonnull Region signingRegion,
             @CheckForNull AwsSdk2TransportOptions options) {
-        this(httpClient, null, host, signingServiceName, signingRegion, options);
-    }
-
-    /**
-     * Create an {@link OpenSearchTransport} with an asynchronous AWS HTTP client
-     * <p>
-     * Note that synchronous OpenSearch requests sent through this transport will be dispatched
-     * using the asynchronous client, but the calling thread will block until they are complete.
-     *
-     * @param asyncHttpClient HTTP client to use for OpenSearch requests.
-     * @param host The target host.
-     * @param signingRegion The AWS region for which requests will be signed. This should typically match region in `host`.
-     * @param options Options that apply to all requests. Can be null. Create with
-     *                {@link AwsSdk2TransportOptions#builder()} and use these to specify non-default credentials,
-     *                compression options, etc.
-     */
-    public AwsSdk2Transport(
-            @Nonnull SdkAsyncHttpClient asyncHttpClient,
-            @Nonnull String host,
-            @Nonnull Region signingRegion,
-            @CheckForNull AwsSdk2TransportOptions options) {
-        this(null, asyncHttpClient, host, "es", signingRegion, options);
+        this(syncHttpClient, host, "es", signingRegion, options);
     }
 
     /**
      * Create an {@link OpenSearchTransport} with an asynchronous AWS HTTP client.
      * <p>
-     * Note that synchronous OpenSearch requests sent through this transport will be dispatched
-     * using the asynchronous client, but the calling thread will block until they are complete.
+     * Note that asynchronous OpenSearch requests sent through this transport will be dispatched
+     * *synchronously* on the calling thread.
      *
-     * @param asyncHttpClient HTTP client to use for OpenSearch requests.
-     * @param host The target host.
-     * @param signingServiceName The AWS signing service name, one of `es` (Amazon OpenSearch) or `aoss` (Amazon OpenSearch Serverless).
+     * @param asyncHttpClient Asynchronous HTTP client to use for OpenSearch requests.
+     * @param host The fully qualified domain name to connect to.
      * @param signingRegion The AWS region for which requests will be signed. This should typically match the region in `host`.
+     * @param signingServiceName The AWS signing service name, one of `es` (Amazon OpenSearch) or `aoss` (Amazon OpenSearch Serverless).
      * @param options Options that apply to all requests. Can be null. Create with
      *                {@link AwsSdk2TransportOptions#builder()} and use these to specify non-default credentials,
      *                compression options, etc.
      */
     public AwsSdk2Transport(
-            @Nonnull SdkAsyncHttpClient asyncHttpClient,
+            @CheckForNull SdkAsyncHttpClient asyncHttpClient,
             @Nonnull String host,
             @Nonnull String signingServiceName,
             @Nonnull Region signingRegion,
             @CheckForNull AwsSdk2TransportOptions options) {
-        this(null, asyncHttpClient, host, signingServiceName, signingRegion, options);
+        this((SdkAutoCloseable) asyncHttpClient, host, signingServiceName, signingRegion, options);
     }
 
     /**
-     * Create an {@link OpenSearchTransport} with both synchronous and asynchronous AWS HTTP clients.
-     * <p>
-     * The synchronous client will be used for synchronous OpenSearch requests, and the asynchronous client
-     * will be used for asynchronous HTTP requests.
+     * Create an {@link OpenSearchTransport} with a synchronous AWS HTTP client.
      *
-     * @param httpClient HTTP client to use for OpenSearch requests.
-     * @param asyncHttpClient HTTP client to use for synchronous OpenSearch requests.
+     * @param syncHttpClient Synchronous HTTP client to use for OpenSearch requests.
      * @param host The fully qualified domain name to connect to.
      * @param signingRegion The AWS region for which requests will be signed. This should typically match the region in `host`.
+     * @param signingServiceName The AWS signing service name, one of `es` (Amazon OpenSearch) or `aoss` (Amazon OpenSearch Serverless).
      * @param options Options that apply to all requests. Can be null. Create with
      *                {@link AwsSdk2TransportOptions#builder()} and use these to specify non-default credentials,
      *                compression options, etc.
      */
     public AwsSdk2Transport(
-            @CheckForNull SdkHttpClient httpClient,
-            @CheckForNull SdkAsyncHttpClient asyncHttpClient,
+            @CheckForNull SdkHttpClient syncHttpClient,
             @Nonnull String host,
+            @Nonnull String signingServiceName,
             @Nonnull Region signingRegion,
             @CheckForNull AwsSdk2TransportOptions options) {
-        this(httpClient, asyncHttpClient, host, "es", signingRegion, options);
+        this((SdkAutoCloseable) syncHttpClient, host, signingServiceName, signingRegion, options);
     }
 
-    /**
-     * Create an {@link OpenSearchTransport} with both synchronous and asynchronous AWS HTTP clients.
-     * <p>
-     * The synchronous client will be used for synchronous OpenSearch requests, and the asynchronous client
-     * will be used for asynchronous HTTP requests.
-     *
-     * @param httpClient HTTP client to use for OpenSearch requests.
-     * @param asyncHttpClient HTTP client to use for synchronous OpenSearch requests.
-     * @param host The fully qualified domain name to connect to.
-     * @param signingRegion The AWS region for which requests will be signed. This should typically match the region in `host`.
-     * @param signingServiceName The AWS signing service name, one of `es` (Amazon OpenSearch) or `aoss` (Amazon OpenSearch Serverless).
-     * @param options Options that apply to all requests. Can be null. Create with
-     *                {@link AwsSdk2TransportOptions#builder()} and use these to specify non-default credentials,
-     *                compression options, etc.
-     */
-    public AwsSdk2Transport(
-            @CheckForNull SdkHttpClient httpClient,
-            @CheckForNull SdkAsyncHttpClient asyncHttpClient,
+    private AwsSdk2Transport(
+            @CheckForNull SdkAutoCloseable httpClient,
             @Nonnull String host,
             @Nonnull String signingServiceName,
             @Nonnull Region signingRegion,
             @CheckForNull AwsSdk2TransportOptions options) {
-        if (httpClient == null && asyncHttpClient == null)
-        {
-            throw new IllegalArgumentException("At least one SdkHttpClient or SdkAsyncHttpClient must be provided");
-        }
         Objects.requireNonNull(host, "Target OpenSearch service host must not be null");
         this.httpClient = httpClient;
-        this.asyncHttpClient = asyncHttpClient;
         this.host = host;
         this.signingServiceName = signingServiceName;
         this.signingRegion = signingRegion;
@@ -237,11 +187,11 @@ public <RequestT, ResponseT, ErrorT> ResponseT performRequest(
         OpenSearchRequestBodyBuffer requestBody = prepareRequestBody(request, endpoint, options);
         SdkHttpFullRequest clientReq = prepareRequest(request, endpoint, options, requestBody);
 
-        if (httpClient != null) {
-            return executeSync(clientReq, endpoint, options);
-        } else {
+        if (httpClient instanceof SdkHttpClient) {
+            return executeSync((SdkHttpClient) httpClient, clientReq, endpoint, options);
+        } else if (httpClient instanceof SdkAsyncHttpClient) {
             try {
-                return executeAsync(clientReq, requestBody, endpoint, options).get();
+                return executeAsync((SdkAsyncHttpClient) httpClient, clientReq, requestBody, endpoint, options).get();
             } catch (ExecutionException e) {
                 Throwable cause = e.getCause();
                 if (cause != null) {
@@ -257,6 +207,8 @@ public <RequestT, ResponseT, ErrorT> ResponseT performRequest(
             } catch (InterruptedException e) {
                 throw new IOException("HttpRequest was interrupted", e);
             }
+        } else {
+            throw new IOException("invalid httpClient: " + httpClient);
         }
     }
 
@@ -269,11 +221,13 @@ public <RequestT, ResponseT, ErrorT> CompletableFuture<ResponseT> performRequest
         try {
             OpenSearchRequestBodyBuffer requestBody = prepareRequestBody(request, endpoint, options);
             SdkHttpFullRequest clientReq = prepareRequest(request, endpoint, options, requestBody);
-            if (asyncHttpClient != null) {
-                return executeAsync(clientReq, requestBody, endpoint, options);
-            } else {
-                ResponseT result = executeSync(clientReq, endpoint, options);
+            if (httpClient instanceof SdkAsyncHttpClient) {
+                return executeAsync((SdkAsyncHttpClient) httpClient, clientReq, requestBody, endpoint, options);
+            } else if (httpClient instanceof SdkHttpClient) {
+                ResponseT result = executeSync((SdkHttpClient) httpClient, clientReq, endpoint, options);
                 return CompletableFuture.completedFuture(result);
+            } else {
+                throw new IOException("invalid httpClient: " + httpClient);
             }
         } catch (Throwable e) {
             CompletableFuture<ResponseT> cf = new CompletableFuture<>();
@@ -418,6 +372,7 @@ private void applyOptionsHeaders(SdkHttpFullRequest.Builder builder, TransportOp
     }
 
     private <ResponseT> ResponseT executeSync(
+            SdkHttpClient syncHttpClient,
             SdkHttpFullRequest httpRequest,
             Endpoint<?, ResponseT, ?> endpoint,
             TransportOptions options
@@ -427,7 +382,7 @@ private <ResponseT> ResponseT executeSync(
         if (httpRequest.contentStreamProvider().isPresent()) {
             executeRequest.contentStreamProvider(httpRequest.contentStreamProvider().get());
         }
-        HttpExecuteResponse executeResponse = httpClient.prepareRequest(executeRequest.build()).call();
+        HttpExecuteResponse executeResponse = syncHttpClient.prepareRequest(executeRequest.build()).call();
         AbortableInputStream bodyStream = null;
         try {
             bodyStream = executeResponse.responseBody().orElse(null);
@@ -441,6 +396,7 @@ private <ResponseT> ResponseT executeSync(
     }
 
     private <ResponseT> CompletableFuture<ResponseT> executeAsync(
+            SdkAsyncHttpClient asyncHttpClient,
             SdkHttpFullRequest httpRequest,
             @CheckForNull OpenSearchRequestBodyBuffer requestBody,
             Endpoint<?, ResponseT, ?> endpoint,
@@ -543,7 +499,6 @@ private <ResponseT, ErrorT> ResponseT parseResponse(
                 ResponseT response = (ResponseT) new BooleanResponse(bep.getResult(statusCode));
                 return response;
             } else if (endpoint instanceof JsonEndpoint) {
-                @SuppressWarnings("unchecked")
                 JsonEndpoint<?, ResponseT, ?> jsonEndpoint = (JsonEndpoint<?, ResponseT, ?>) endpoint;
                 // Successful response
                 ResponseT response = null;
diff --git a/java-client/src/test/java/org/opensearch/client/opensearch/integTest/aws/AwsSdk2TransportTestCase.java b/java-client/src/test/java/org/opensearch/client/opensearch/integTest/aws/AwsSdk2TransportTestCase.java
index fa1d33f39..8adcd4300 100644
--- a/java-client/src/test/java/org/opensearch/client/opensearch/integTest/aws/AwsSdk2TransportTestCase.java
+++ b/java-client/src/test/java/org/opensearch/client/opensearch/integTest/aws/AwsSdk2TransportTestCase.java
@@ -8,7 +8,6 @@
 
 package org.opensearch.client.opensearch.integTest.aws;
 
-
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
@@ -42,7 +41,6 @@
 import java.util.Objects;
 import java.util.concurrent.CompletableFuture;
 
-
 public abstract class AwsSdk2TransportTestCase {
     public static final String TEST_INDEX = "opensearch-java-integtest";
 
@@ -85,16 +83,14 @@ protected OpenSearchClient getClient(
                     getTestClusterHost(),
                     getTestClusterServiceName(),
                     getTestClusterRegion(),
-                    getTransportOptions().build()
-            );
+                    getTransportOptions().build());
         } else {
             transport = new AwsSdk2Transport(
                     getHttpClient(),
                     getTestClusterHost(),
                     getTestClusterServiceName(),
                     getTestClusterRegion(),
-                    getTransportOptions().build()
-            );
+                    getTransportOptions().build());
         }
         return new OpenSearchClient(transport);
     }
@@ -111,16 +107,14 @@ protected OpenSearchAsyncClient getAsyncClient(
                     getTestClusterHost(),
                     getTestClusterServiceName(),
                     getTestClusterRegion(),
-                    getTransportOptions().build()
-            );
+                    getTransportOptions().build());
         } else {
             transport = new AwsSdk2Transport(
                     getHttpClient(),
                     getTestClusterHost(),
                     getTestClusterServiceName(),
                     getTestClusterRegion(),
-                    getTransportOptions().build()
-            );
+                    getTransportOptions().build());
         }
         return new OpenSearchAsyncClient(transport);
     }
@@ -137,16 +131,14 @@ protected OpenSearchIndicesClient getIndexesClient(
                     getTestClusterHost(),
                     getTestClusterServiceName(),
                     getTestClusterRegion(),
-                    getTransportOptions().build()
-            );
+                    getTransportOptions().build());
         } else {
             transport = new AwsSdk2Transport(
                     getHttpClient(),
                     getTestClusterHost(),
                     getTestClusterServiceName(),
                     getTestClusterRegion(),
-                    getTransportOptions().build()
-            );
+                    getTransportOptions().build());
         }
         return new OpenSearchIndicesClient(transport);
     }
@@ -171,6 +163,7 @@ public static void cleanupClients() throws IOException {
         if (httpClient != null) {
             try {
                 httpClient.close();
+                httpClient = null;
             } catch (Throwable e) {
                 // Not our problem
             }
@@ -178,6 +171,7 @@ public static void cleanupClients() throws IOException {
         if (asyncHttpClient != null) {
             try {
                 asyncHttpClient.close();
+                asyncHttpClient = null;
             } catch (Throwable e) {
                 // Not our problem
             }
@@ -204,10 +198,8 @@ public void resetTestIndex(boolean async) throws Exception {
             IndexState indexInfo = client.get(b -> b.index(TEST_INDEX)).get(TEST_INDEX);
             if (indexInfo != null) {
                 indexExists = true;
-
             }
-        } catch (
-                OpenSearchException e) {
+        } catch (OpenSearchException e) {
             if (e.status() != 404) {
                 throw e;
             }
@@ -237,17 +229,14 @@ protected SearchResponse<SimplePojo> query(OpenSearchClient client, String title
                 .ignoreThrottled(false)
                 .sort(
                         new SortOptions.Builder().score(o -> o.order(SortOrder.Desc)).build(),
-                        new SortOptions.Builder().doc(o -> o.order(SortOrder.Desc)).build()
-                )
+                        new SortOptions.Builder().doc(o -> o.order(SortOrder.Desc)).build())
                 .query(query);
 
-
         return client.search(req.build(), SimplePojo.class);
     }
 
     protected CompletableFuture<SearchResponse<SimplePojo>> query(
-            OpenSearchAsyncClient client, String title, String text
-    ) {
+            OpenSearchAsyncClient client, String title, String text) {
         var query = Query.of(qb -> {
             if (title != null) {
                 qb.match(mb -> mb.field("title").query(vb -> vb.stringValue(title)));
@@ -264,8 +253,7 @@ protected CompletableFuture<SearchResponse<SimplePojo>> query(
                 .ignoreThrottled(false)
                 .sort(
                         new SortOptions.Builder().score(o -> o.order(SortOrder.Desc)).build(),
-                        new SortOptions.Builder().doc(o -> o.order(SortOrder.Desc)).build()
-                )
+                        new SortOptions.Builder().doc(o -> o.order(SortOrder.Desc)).build())
                 .query(query);
 
         try {