diff --git a/legacy/src/main/java/org/opensearch/sql/legacy/executor/GetIndexRequestRestListener.java b/legacy/src/main/java/org/opensearch/sql/legacy/executor/GetIndexRequestRestListener.java
index ebd9648d5e..1adb0e745e 100644
--- a/legacy/src/main/java/org/opensearch/sql/legacy/executor/GetIndexRequestRestListener.java
+++ b/legacy/src/main/java/org/opensearch/sql/legacy/executor/GetIndexRequestRestListener.java
@@ -6,16 +6,13 @@
 
 package org.opensearch.sql.legacy.executor;
 
-import com.carrotsearch.hppc.cursors.ObjectObjectCursor;
 import java.io.IOException;
 import java.util.List;
-import java.util.Map;
 
 import org.opensearch.action.admin.indices.get.GetIndexRequest;
 import org.opensearch.action.admin.indices.get.GetIndexResponse;
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.core.xcontent.XContentBuilder;
@@ -25,7 +22,6 @@
 import org.opensearch.rest.RestStatus;
 import org.opensearch.rest.action.RestBuilderListener;
 import org.opensearch.sql.legacy.antlr.semantic.SemanticAnalysisException;
-import org.opensearch.sql.legacy.domain.Field;
 
 /**
  * Created by Eliran on 6/10/2015.
diff --git a/legacy/src/test/java/org/opensearch/sql/legacy/util/CheckScriptContents.java b/legacy/src/test/java/org/opensearch/sql/legacy/util/CheckScriptContents.java
index 44baa8050b..595b6987a7 100644
--- a/legacy/src/test/java/org/opensearch/sql/legacy/util/CheckScriptContents.java
+++ b/legacy/src/test/java/org/opensearch/sql/legacy/util/CheckScriptContents.java
@@ -37,10 +37,8 @@
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.IndexNameExpressionResolver;
-import org.opensearch.cluster.metadata.MappingMetadata;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.cluster.service.ClusterService;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.DeprecationHandler;
 import org.opensearch.core.xcontent.NamedXContentRegistry;
diff --git a/opensearch/src/main/java/org/opensearch/sql/opensearch/client/OpenSearchNodeClient.java b/opensearch/src/main/java/org/opensearch/sql/opensearch/client/OpenSearchNodeClient.java
index 1c1498feb5..b26680b3ba 100644
--- a/opensearch/src/main/java/org/opensearch/sql/opensearch/client/OpenSearchNodeClient.java
+++ b/opensearch/src/main/java/org/opensearch/sql/opensearch/client/OpenSearchNodeClient.java
@@ -112,11 +112,11 @@ public Map<String, Integer> getIndexMaxResultWindows(String... indexExpression)
       GetSettingsResponse settingsResponse =
           client.admin().indices().prepareGetSettings(indexExpression).setLocal(true).get();
       ImmutableMap.Builder<String, Integer> result = ImmutableMap.builder();
-      for (ObjectObjectCursor<String, Settings> indexToSetting :
-          settingsResponse.getIndexToSettings()) {
-        Settings settings = indexToSetting.value;
+      for (Map.Entry<String, Settings> indexToSetting :
+          settingsResponse.getIndexToSettings().entrySet()) {
+        Settings settings = indexToSetting.getValue();
         result.put(
-            indexToSetting.key,
+            indexToSetting.getKey(),
             settings.getAsInt(
                 IndexSettings.MAX_RESULT_WINDOW_SETTING.getKey(),
                 IndexSettings.MAX_RESULT_WINDOW_SETTING.getDefault(settings)));
diff --git a/opensearch/src/main/java/org/opensearch/sql/opensearch/client/OpenSearchRestClient.java b/opensearch/src/main/java/org/opensearch/sql/opensearch/client/OpenSearchRestClient.java
index d9f9dbbe5d..66cc067541 100644
--- a/opensearch/src/main/java/org/opensearch/sql/opensearch/client/OpenSearchRestClient.java
+++ b/opensearch/src/main/java/org/opensearch/sql/opensearch/client/OpenSearchRestClient.java
@@ -30,7 +30,6 @@
 import org.opensearch.client.indices.GetMappingsResponse;
 import org.opensearch.client.node.NodeClient;
 import org.opensearch.cluster.metadata.AliasMetadata;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.sql.opensearch.mapping.IndexMapping;
 import org.opensearch.sql.opensearch.request.OpenSearchRequest;
@@ -85,21 +84,21 @@ public Map<String, Integer> getIndexMaxResultWindows(String... indexExpression)
         .indices(indexExpression).includeDefaults(true);
     try {
       GetSettingsResponse response = client.indices().getSettings(request, RequestOptions.DEFAULT);
-      ImmutableOpenMap<String, Settings> settings = response.getIndexToSettings();
-      ImmutableOpenMap<String, Settings> defaultSettings = response.getIndexToDefaultSettings();
+      Map<String, Settings> settings = response.getIndexToSettings();
+      Map<String, Settings> defaultSettings = response.getIndexToDefaultSettings();
       Map<String, Integer> result = new HashMap<>();
 
-      defaultSettings.forEach(entry -> {
-        Integer maxResultWindow = entry.value.getAsInt("index.max_result_window", null);
+      defaultSettings.forEach((key, value) -> {
+        Integer maxResultWindow = value.getAsInt("index.max_result_window", null);
         if (maxResultWindow != null) {
-          result.put(entry.key, maxResultWindow);
+          result.put(key, maxResultWindow);
         }
       });
 
-      settings.forEach(entry -> {
-        Integer maxResultWindow = entry.value.getAsInt("index.max_result_window", null);
+      settings.forEach((key, value) -> {
+        Integer maxResultWindow = value.getAsInt("index.max_result_window", null);
         if (maxResultWindow != null) {
-          result.put(entry.key, maxResultWindow);
+          result.put(key, maxResultWindow);
         }
       });
 
diff --git a/opensearch/src/test/java/org/opensearch/sql/opensearch/client/OpenSearchNodeClientTest.java b/opensearch/src/test/java/org/opensearch/sql/opensearch/client/OpenSearchNodeClientTest.java
index 352635bfc3..8af9a4bbfa 100644
--- a/opensearch/src/test/java/org/opensearch/sql/opensearch/client/OpenSearchNodeClientTest.java
+++ b/opensearch/src/test/java/org/opensearch/sql/opensearch/client/OpenSearchNodeClientTest.java
@@ -55,7 +55,6 @@
 import org.opensearch.cluster.metadata.AliasMetadata;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.util.concurrent.ThreadContext;
 import org.opensearch.common.xcontent.XContentType;
@@ -425,10 +424,8 @@ private void mockNodeClientSettings(String indexName, String indexMetadata)
     GetSettingsResponse mockResponse = mock(GetSettingsResponse.class);
     when(nodeClient.admin().indices().prepareGetSettings(any()).setLocal(anyBoolean()).get())
         .thenReturn(mockResponse);
-    ImmutableOpenMap<String, Settings> metadata =
-        new ImmutableOpenMap.Builder<String, Settings>()
-            .fPut(indexName, IndexMetadata.fromXContent(createParser(indexMetadata)).getSettings())
-            .build();
+    Map<String, Settings> metadata = Map.of(indexName,
+        IndexMetadata.fromXContent(createParser(indexMetadata)).getSettings());
 
     when(mockResponse.getIndexToSettings()).thenReturn(metadata);
   }
diff --git a/opensearch/src/test/java/org/opensearch/sql/opensearch/client/OpenSearchRestClientTest.java b/opensearch/src/test/java/org/opensearch/sql/opensearch/client/OpenSearchRestClientTest.java
index dd5bfd4e6f..141e21c38a 100644
--- a/opensearch/src/test/java/org/opensearch/sql/opensearch/client/OpenSearchRestClientTest.java
+++ b/opensearch/src/test/java/org/opensearch/sql/opensearch/client/OpenSearchRestClientTest.java
@@ -49,7 +49,6 @@
 import org.opensearch.client.indices.GetMappingsResponse;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.cluster.metadata.MappingMetadata;
-import org.opensearch.common.collect.ImmutableOpenMap;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.DeprecationHandler;
@@ -232,9 +231,9 @@ void getIndexMaxResultWindowsSettings() throws IOException {
         .put("index.max_result_window", maxResultWindow)
         .build();
     Settings emptySettings = Settings.builder().build();
-    ImmutableOpenMap<String, Settings> indexToSettings =
+    Map<String, Settings> indexToSettings =
         mockSettings(indexName, maxResultWindowSettings);
-    ImmutableOpenMap<String, Settings> indexToDefaultSettings =
+    Map<String, Settings> indexToDefaultSettings =
         mockSettings(indexName, emptySettings);
     when(response.getIndexToSettings()).thenReturn(indexToSettings);
     when(response.getIndexToDefaultSettings()).thenReturn(indexToDefaultSettings);
@@ -256,9 +255,9 @@ void getIndexMaxResultWindowsDefaultSettings() throws IOException {
         .put("index.max_result_window", maxResultWindow)
         .build();
     Settings emptySettings = Settings.builder().build();
-    ImmutableOpenMap<String, Settings> indexToSettings =
+    Map<String, Settings> indexToSettings =
         mockSettings(indexName, emptySettings);
-    ImmutableOpenMap<String, Settings> indexToDefaultSettings =
+    Map<String, Settings> indexToDefaultSettings =
         mockSettings(indexName, maxResultWindowSettings);
     when(response.getIndexToSettings()).thenReturn(indexToSettings);
     when(response.getIndexToDefaultSettings()).thenReturn(indexToDefaultSettings);
@@ -427,10 +426,8 @@ private Map<String, MappingMetadata> mockFieldMappings(String indexName, String
     return ImmutableMap.of(indexName, IndexMetadata.fromXContent(createParser(mappings)).mapping());
   }
 
-  private ImmutableOpenMap<String, Settings> mockSettings(String indexName, Settings settings) {
-    ImmutableOpenMap.Builder<String, Settings> indexToSettingsBuilder = ImmutableOpenMap.builder();
-    indexToSettingsBuilder.put(indexName, settings);
-    return indexToSettingsBuilder.build();
+  private Map<String, Settings> mockSettings(String indexName, Settings settings) {
+    return Map.of(indexName, settings);
   }
 
   private XContentParser createParser(String mappings) throws IOException {