diff --git a/qa/restart-upgrade/src/test/java/org/opensearch/knn/bwc/IndexingIT.java b/qa/restart-upgrade/src/test/java/org/opensearch/knn/bwc/IndexingIT.java
index bf4c8f7ec..c344581fe 100644
--- a/qa/restart-upgrade/src/test/java/org/opensearch/knn/bwc/IndexingIT.java
+++ b/qa/restart-upgrade/src/test/java/org/opensearch/knn/bwc/IndexingIT.java
@@ -61,6 +61,23 @@ public void testKNNIndexDefaultLegacyFieldMapping() throws Exception {
         }
     }
 
+    // ensure that index is created using legacy mapping in old cluster, and, then docs are added, and, new docs are added
+    // in new cluster, search should return docs when it was indexed during old cluster and new cluster.
+    public void testKNNIndexDefaultEngine() throws Exception {
+        waitForClusterHealthGreen(NODES_BWC_CLUSTER);
+        if (isRunningAgainstOldCluster()) {
+            createKnnIndex(testIndex, getKNNDefaultIndexSettings(), createKnnIndexMapping(TEST_FIELD, DIMENSIONS));
+            addKNNDocs(testIndex, TEST_FIELD, DIMENSIONS, DOC_ID, 5);
+            // Flush to ensure that index is not re-indexed when node comes back up
+            flush(testIndex, true);
+        } else {
+            validateKNNSearch(testIndex, TEST_FIELD, DIMENSIONS, 5, 5);
+            addKNNDocs(testIndex, TEST_FIELD, DIMENSIONS, 5, 5);
+            validateKNNSearch(testIndex, TEST_FIELD, DIMENSIONS, 10, 10);
+            deleteKNNIndex(testIndex);
+        }
+    }
+
     // Ensure that when segments created with old mapping are forcemerged in new cluster, they
     // succeed
     public void testKNNIndexDefaultLegacyFieldMappingForceMerge() throws Exception {
diff --git a/release-notes/opensearch-knn.release-notes-2.18.0.0.md b/release-notes/opensearch-knn.release-notes-2.18.0.0.md
index 9e85fd9ca..844605a8e 100644
--- a/release-notes/opensearch-knn.release-notes-2.18.0.0.md
+++ b/release-notes/opensearch-knn.release-notes-2.18.0.0.md
@@ -15,6 +15,7 @@ Compatible with OpenSearch 2.18.0
 * Add CompressionLevel Calculation for PQ [#2200](https://github.com/opensearch-project/k-NN/pull/2200)
 * Remove FSDirectory dependency from native engine constructing side and deprecated FileWatcher [#2182](https://github.com/opensearch-project/k-NN/pull/2182)
 * Update approximate_threshold to 15K documents [#2229](https://github.com/opensearch-project/k-NN/pull/2229)
+* Update default engine to FAISS [#2221](https://github.com/opensearch-project/k-NN/pull/2221)
 ### Bug Fixes
 * Add DocValuesProducers for releasing memory when close index [#1946](https://github.com/opensearch-project/k-NN/pull/1946)
 * KNN80DocValues should only be considered for BinaryDocValues fields [#2147](https://github.com/opensearch-project/k-NN/pull/2147)
diff --git a/src/main/java/org/opensearch/knn/index/engine/EngineResolver.java b/src/main/java/org/opensearch/knn/index/engine/EngineResolver.java
index daae361e4..d52c21c4c 100644
--- a/src/main/java/org/opensearch/knn/index/engine/EngineResolver.java
+++ b/src/main/java/org/opensearch/knn/index/engine/EngineResolver.java
@@ -49,7 +49,7 @@ public KNNEngine resolveEngine(
 
         // For 1x, we need to default to faiss if mode is provided and use nmslib otherwise
         if (CompressionLevel.isConfigured(compressionLevel) == false || compressionLevel == CompressionLevel.x1) {
-            return mode == Mode.ON_DISK ? KNNEngine.FAISS : KNNEngine.DEFAULT;
+            return mode == Mode.ON_DISK ? KNNEngine.FAISS : KNNEngine.NMSLIB;
         }
 
         // Lucene is only engine that supports 4x - so we have to default to it here.
diff --git a/src/main/java/org/opensearch/knn/index/engine/KNNEngine.java b/src/main/java/org/opensearch/knn/index/engine/KNNEngine.java
index 80b9f32a6..1e560a11b 100644
--- a/src/main/java/org/opensearch/knn/index/engine/KNNEngine.java
+++ b/src/main/java/org/opensearch/knn/index/engine/KNNEngine.java
@@ -29,7 +29,7 @@ public enum KNNEngine implements KNNLibrary {
     FAISS(FAISS_NAME, Faiss.INSTANCE),
     LUCENE(LUCENE_NAME, Lucene.INSTANCE);
 
-    public static final KNNEngine DEFAULT = NMSLIB;
+    public static final KNNEngine DEFAULT = FAISS;
 
     private static final Set<KNNEngine> CUSTOM_SEGMENT_FILE_ENGINES = ImmutableSet.of(KNNEngine.NMSLIB, KNNEngine.FAISS);
     private static final Set<KNNEngine> ENGINES_SUPPORTING_FILTERS = ImmutableSet.of(KNNEngine.LUCENE, KNNEngine.FAISS);
diff --git a/src/main/java/org/opensearch/knn/index/mapper/KNNVectorFieldMapper.java b/src/main/java/org/opensearch/knn/index/mapper/KNNVectorFieldMapper.java
index 18d4f7b64..beceadde5 100644
--- a/src/main/java/org/opensearch/knn/index/mapper/KNNVectorFieldMapper.java
+++ b/src/main/java/org/opensearch/knn/index/mapper/KNNVectorFieldMapper.java
@@ -500,8 +500,7 @@ private void resolveKNNMethodComponents(
                     .build()
             );
 
-            // If the original parameters are from legacy
-            if (builder.originalParameters.isLegacyMapping()) {
+            if (useKNNMethodContextFromLegacy(builder, parserContext)) {
                 // Then create KNNMethodContext to be used from the legacy index settings
                 builder.originalParameters.setResolvedKnnMethodContext(
                     createKNNMethodContextFromLegacy(parserContext.getSettings(), parserContext.indexVersionCreated(), resolvedSpaceType)
@@ -550,6 +549,12 @@ private void setEngine(final KNNMethodContext knnMethodContext, KNNEngine knnEng
         }
     }
 
+    static boolean useKNNMethodContextFromLegacy(Builder builder, Mapper.TypeParser.ParserContext parserContext) {
+        // If the original parameters are from legacy, and it is created on or before 2_17_2 since default is changed to
+        // FAISS starting 2_18, which doesn't support accepting algo params from index settings
+        return parserContext.indexVersionCreated().onOrBefore(Version.V_2_17_2) && builder.originalParameters.isLegacyMapping();
+    }
+
     // We store the version of the index with the mapper as different version of Opensearch has different default
     // values of KNN engine Algorithms hyperparameters.
     protected Version indexCreatedVersion;
diff --git a/src/main/java/org/opensearch/knn/index/query/KNNWeight.java b/src/main/java/org/opensearch/knn/index/query/KNNWeight.java
index b5b2a5d22..04c2ce587 100644
--- a/src/main/java/org/opensearch/knn/index/query/KNNWeight.java
+++ b/src/main/java/org/opensearch/knn/index/query/KNNWeight.java
@@ -251,7 +251,7 @@ private Map<Integer, Float> doANNSearch(
             spaceType = modelMetadata.getSpaceType();
             vectorDataType = modelMetadata.getVectorDataType();
         } else {
-            String engineName = fieldInfo.attributes().getOrDefault(KNN_ENGINE, KNNEngine.NMSLIB.getName());
+            String engineName = fieldInfo.attributes().getOrDefault(KNN_ENGINE, KNNEngine.DEFAULT.getName());
             knnEngine = KNNEngine.getEngine(engineName);
             String spaceTypeName = fieldInfo.attributes().getOrDefault(SPACE_TYPE, SpaceType.L2.getValue());
             spaceType = SpaceType.getSpace(spaceTypeName);
diff --git a/src/test/java/org/opensearch/knn/KNNSingleNodeTestCase.java b/src/test/java/org/opensearch/knn/KNNSingleNodeTestCase.java
index 587e80e5d..7bfce5b94 100644
--- a/src/test/java/org/opensearch/knn/KNNSingleNodeTestCase.java
+++ b/src/test/java/org/opensearch/knn/KNNSingleNodeTestCase.java
@@ -16,6 +16,7 @@
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.xcontent.XContentHelper;
 import org.opensearch.knn.index.KNNSettings;
+import org.opensearch.knn.index.engine.KNNEngine;
 import org.opensearch.knn.index.query.KNNQueryBuilder;
 import org.opensearch.knn.index.memory.NativeMemoryCacheManager;
 import org.opensearch.knn.index.memory.NativeMemoryLoadStrategy;
@@ -50,6 +51,7 @@
 import static org.mockito.Mockito.when;
 import static org.opensearch.knn.common.KNNConstants.DIMENSION;
 import static org.opensearch.knn.common.KNNConstants.KNN_ENGINE;
+import static org.opensearch.knn.common.KNNConstants.METHOD_HNSW;
 import static org.opensearch.knn.common.KNNConstants.METHOD_PARAMETER_SPACE_TYPE;
 import static org.opensearch.knn.common.KNNConstants.MODEL_BLOB_PARAMETER;
 import static org.opensearch.knn.common.KNNConstants.MODEL_DESCRIPTION;
@@ -109,6 +111,22 @@ protected void createKnnIndexMapping(String indexName, String fieldName, Integer
     /**
      * Create simple k-NN mapping with engine
      */
+    protected void createKnnIndexMapping(String indexName, String fieldName, Integer dimensions, KNNEngine engine) throws IOException {
+        PutMappingRequest request = new PutMappingRequest(indexName);
+        XContentBuilder xContentBuilder = XContentFactory.jsonBuilder().startObject().startObject("properties");
+        xContentBuilder.startObject(fieldName);
+        xContentBuilder.field("type", "knn_vector").field("dimension", dimensions.toString());
+        xContentBuilder.startObject("method");
+        xContentBuilder.field("name", METHOD_HNSW);
+        xContentBuilder.field(KNN_ENGINE, engine.getName());
+        xContentBuilder.endObject();
+        xContentBuilder.endObject();
+        xContentBuilder.endObject();
+        xContentBuilder.endObject();
+        request.source(xContentBuilder);
+        OpenSearchAssertions.assertAcked(client().admin().indices().putMapping(request).actionGet());
+    }
+
     protected void updateIndexSetting(String indexName, Settings setting) {
         UpdateSettingsRequest request = new UpdateSettingsRequest(setting, indexName);
         OpenSearchAssertions.assertAcked(client().admin().indices().updateSettings(request).actionGet());
diff --git a/src/test/java/org/opensearch/knn/index/KNNIndexShardTests.java b/src/test/java/org/opensearch/knn/index/KNNIndexShardTests.java
index c25d2a390..d01c3a0b4 100644
--- a/src/test/java/org/opensearch/knn/index/KNNIndexShardTests.java
+++ b/src/test/java/org/opensearch/knn/index/KNNIndexShardTests.java
@@ -19,6 +19,7 @@
 import org.opensearch.index.IndexService;
 import org.opensearch.index.engine.Engine;
 import org.opensearch.index.shard.IndexShard;
+import org.opensearch.knn.index.engine.KNNEngine;
 import org.opensearch.knn.index.memory.NativeMemoryCacheManager;
 
 import java.io.IOException;
@@ -108,7 +109,7 @@ public void testWarmup_shardNotPresentInCache() throws InterruptedException, Exe
 
     public void testGetAllEngineFileContexts() throws IOException, ExecutionException, InterruptedException {
         IndexService indexService = createKNNIndex(testIndexName);
-        createKnnIndexMapping(testIndexName, testFieldName, dimensions);
+        createKnnIndexMapping(testIndexName, testFieldName, dimensions, KNNEngine.NMSLIB);
         updateIndexSetting(testIndexName, Settings.builder().put(KNNSettings.INDEX_KNN_ADVANCED_APPROXIMATE_THRESHOLD, 0).build());
 
         IndexShard indexShard = indexService.iterator().next();
diff --git a/src/test/java/org/opensearch/knn/index/NmslibIT.java b/src/test/java/org/opensearch/knn/index/NmslibIT.java
index 495fc55ba..23d35d39e 100644
--- a/src/test/java/org/opensearch/knn/index/NmslibIT.java
+++ b/src/test/java/org/opensearch/knn/index/NmslibIT.java
@@ -36,6 +36,7 @@
 import java.util.TreeMap;
 
 import static org.hamcrest.Matchers.containsString;
+import static org.opensearch.knn.common.KNNConstants.KNN_ENGINE;
 
 public class NmslibIT extends KNNRestTestCase {
 
@@ -281,6 +282,7 @@ public void testCreateIndexWithValidAlgoParams_mapping() {
                 .field("dimension", 2)
                 .startObject(KNNConstants.KNN_METHOD)
                 .field(KNNConstants.METHOD_PARAMETER_SPACE_TYPE, spaceType)
+                .field(KNN_ENGINE, KNNEngine.NMSLIB.getName())
                 .field(KNNConstants.NAME, KNNConstants.METHOD_HNSW)
                 .startObject(KNNConstants.PARAMETERS)
                 .field(KNNConstants.METHOD_PARAMETER_EF_CONSTRUCTION, efConstruction)
@@ -336,6 +338,7 @@ public void testCreateIndexWithValidAlgoParams_mappingAndSettings() {
                 .field("dimension", 2)
                 .startObject(KNNConstants.KNN_METHOD)
                 .field(KNNConstants.METHOD_PARAMETER_SPACE_TYPE, spaceType1)
+                .field(KNN_ENGINE, KNNEngine.NMSLIB.getName())
                 .field(KNNConstants.NAME, KNNConstants.METHOD_HNSW)
                 .startObject(KNNConstants.PARAMETERS)
                 .field(KNNConstants.METHOD_PARAMETER_EF_CONSTRUCTION, efConstruction1)
@@ -363,6 +366,7 @@ public void testCreateIndexWithValidAlgoParams_mappingAndSettings() {
                 .field("dimension", 2)
                 .startObject(KNNConstants.KNN_METHOD)
                 .field(KNNConstants.METHOD_PARAMETER_SPACE_TYPE, spaceType1)
+                .field(KNN_ENGINE, KNNEngine.NMSLIB.getName())
                 .field(KNNConstants.NAME, KNNConstants.METHOD_HNSW)
                 .startObject(KNNConstants.PARAMETERS)
                 .field(KNNConstants.METHOD_PARAMETER_EF_CONSTRUCTION, efConstruction1)
@@ -375,6 +379,7 @@ public void testCreateIndexWithValidAlgoParams_mappingAndSettings() {
                 .field("dimension", 2)
                 .startObject(KNNConstants.KNN_METHOD)
                 .field(KNNConstants.METHOD_PARAMETER_SPACE_TYPE, spaceType2)
+                .field(KNN_ENGINE, KNNEngine.NMSLIB.getName())
                 .field(KNNConstants.NAME, KNNConstants.METHOD_HNSW)
                 .startObject(KNNConstants.PARAMETERS)
                 .field(KNNConstants.METHOD_PARAMETER_EF_CONSTRUCTION, efConstruction2)
diff --git a/src/test/java/org/opensearch/knn/index/VectorDataTypeIT.java b/src/test/java/org/opensearch/knn/index/VectorDataTypeIT.java
index fcfb192ca..2e68339d4 100644
--- a/src/test/java/org/opensearch/knn/index/VectorDataTypeIT.java
+++ b/src/test/java/org/opensearch/knn/index/VectorDataTypeIT.java
@@ -263,29 +263,6 @@ public void testByteVectorDataTypeWithNmslibEngine() {
         assertTrue(ex.getMessage().contains("is not supported for vector data type"));
     }
 
-    @SneakyThrows
-    public void testByteVectorDataTypeWithLegacyFieldMapperKnnIndexSetting() {
-        // Create an index with byte vector data_type and index.knn as true without setting KnnMethodContext,
-        // which should throw an exception because the LegacyFieldMapper will use NMSLIB engine and byte data_type
-        // is not supported for NMSLIB engine.
-        XContentBuilder builder = XContentFactory.jsonBuilder()
-            .startObject()
-            .startObject(PROPERTIES_FIELD)
-            .startObject(FIELD_NAME)
-            .field(TYPE_FIELD_NAME, KNN_VECTOR_TYPE)
-            .field(DIMENSION, 2)
-            .field(VECTOR_DATA_TYPE_FIELD, VectorDataType.BYTE.getValue())
-            .endObject()
-            .endObject()
-            .endObject();
-
-        String mapping = builder.toString();
-
-        ResponseException ex = expectThrows(ResponseException.class, () -> createKnnIndex(INDEX_NAME, mapping));
-        assertTrue(ex.getMessage(), ex.getMessage().contains("is not supported for vector data type"));
-
-    }
-
     public void testDocValuesWithByteVectorDataTypeLuceneEngine() throws Exception {
         createKnnIndexMappingWithLuceneEngine(2, SpaceType.L2, VectorDataType.BYTE.getValue());
         ingestL2ByteTestData();
diff --git a/src/test/java/org/opensearch/knn/index/codec/KNN80Codec/KNN80DocValuesConsumerTests.java b/src/test/java/org/opensearch/knn/index/codec/KNN80Codec/KNN80DocValuesConsumerTests.java
index e1f16006d..c11bc765f 100644
--- a/src/test/java/org/opensearch/knn/index/codec/KNN80Codec/KNN80DocValuesConsumerTests.java
+++ b/src/test/java/org/opensearch/knn/index/codec/KNN80Codec/KNN80DocValuesConsumerTests.java
@@ -279,6 +279,7 @@ public void testAddKNNBinaryField_fromScratch_nmslibLegacy() throws IOException
                 .addAttribute(KNNConstants.HNSW_ALGO_EF_CONSTRUCTION, "512")
                 .addAttribute(KNNConstants.HNSW_ALGO_M, "16")
                 .addAttribute(KNNConstants.SPACE_TYPE, spaceType.getValue())
+                .addAttribute(KNNConstants.KNN_ENGINE, knnEngine.getName())
                 .build() };
 
         FieldInfos fieldInfos = new FieldInfos(fieldInfoArray);
diff --git a/src/test/java/org/opensearch/knn/index/codec/KNNCodecTestCase.java b/src/test/java/org/opensearch/knn/index/codec/KNNCodecTestCase.java
index e6fcb643d..53614c7c4 100644
--- a/src/test/java/org/opensearch/knn/index/codec/KNNCodecTestCase.java
+++ b/src/test/java/org/opensearch/knn/index/codec/KNNCodecTestCase.java
@@ -103,7 +103,7 @@ public class KNNCodecTestCase extends KNNTestCase {
             .vectorDataType(VectorDataType.DEFAULT)
             .build();
         KNNMethodContext knnMethodContext = new KNNMethodContext(
-            KNNEngine.DEFAULT,
+            KNNEngine.NMSLIB,
             SpaceType.DEFAULT,
             new MethodComponentContext(METHOD_HNSW, ImmutableMap.of(METHOD_PARAMETER_M, 16, METHOD_PARAMETER_EF_CONSTRUCTION, 512))
         );
diff --git a/src/test/java/org/opensearch/knn/index/engine/EngineResolverTests.java b/src/test/java/org/opensearch/knn/index/engine/EngineResolverTests.java
index df195883a..291f0c671 100644
--- a/src/test/java/org/opensearch/knn/index/engine/EngineResolverTests.java
+++ b/src/test/java/org/opensearch/knn/index/engine/EngineResolverTests.java
@@ -41,10 +41,10 @@ public void testResolveEngine_whenModeAndCompressionAreFalse_thenDefault() {
         );
     }
 
-    public void testResolveEngine_whenModeSpecifiedAndCompressionIsNotSpecified_thenDefault() {
+    public void testResolveEngine_whenModeSpecifiedAndCompressionIsNotSpecified_thenNMSLIB() {
         assertEquals(KNNEngine.DEFAULT, ENGINE_RESOLVER.resolveEngine(KNNMethodConfigContext.builder().build(), null, false));
         assertEquals(
-            KNNEngine.DEFAULT,
+            KNNEngine.NMSLIB,
             ENGINE_RESOLVER.resolveEngine(
                 KNNMethodConfigContext.builder().mode(Mode.IN_MEMORY).build(),
                 new KNNMethodContext(KNNEngine.DEFAULT, SpaceType.UNDEFINED, MethodComponentContext.EMPTY, false),
@@ -63,7 +63,7 @@ public void testResolveEngine_whenCompressionIs1x_thenEngineBasedOnMode() {
             )
         );
         assertEquals(
-            KNNEngine.DEFAULT,
+            KNNEngine.NMSLIB,
             ENGINE_RESOLVER.resolveEngine(KNNMethodConfigContext.builder().compressionLevel(CompressionLevel.x1).build(), null, false)
         );
     }
diff --git a/src/test/java/org/opensearch/knn/index/engine/KNNEngineTests.java b/src/test/java/org/opensearch/knn/index/engine/KNNEngineTests.java
index 5a6ed8e52..3f356999c 100644
--- a/src/test/java/org/opensearch/knn/index/engine/KNNEngineTests.java
+++ b/src/test/java/org/opensearch/knn/index/engine/KNNEngineTests.java
@@ -25,6 +25,10 @@ public void testDelegateLibraryFunctions() {
         assertEquals(Lucene.INSTANCE.getVersion(), KNNEngine.LUCENE.getVersion());
     }
 
+    public void testGetDefaultEngine_thenReturnFAISS() {
+        assertEquals(KNNEngine.FAISS, KNNEngine.DEFAULT);
+    }
+
     /**
      * Test name getter
      */
diff --git a/src/test/java/org/opensearch/knn/index/mapper/KNNVectorFieldMapperTests.java b/src/test/java/org/opensearch/knn/index/mapper/KNNVectorFieldMapperTests.java
index 98bbf42ca..714723a8e 100644
--- a/src/test/java/org/opensearch/knn/index/mapper/KNNVectorFieldMapperTests.java
+++ b/src/test/java/org/opensearch/knn/index/mapper/KNNVectorFieldMapperTests.java
@@ -65,6 +65,7 @@
 import java.util.Optional;
 import java.util.stream.Collectors;
 
+import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.doNothing;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
@@ -146,7 +147,7 @@ public void testTypeParser_build_fromKnnMethodContext() throws IOException {
         // Check that knnMethodContext takes precedent over both model and legacy
         ModelDao modelDao = mock(ModelDao.class);
 
-        SpaceType spaceType = SpaceType.COSINESIMIL;
+        SpaceType spaceType = SpaceType.DEFAULT;
         int mRight = 17;
         int mWrong = 71;
 
@@ -284,36 +285,43 @@ public void testTypeParser_withDifferentSpaceTypeCombinations_thenSuccess() thro
         );
         assertTrue(knnVectorFieldMapper.fieldType().getKnnMappingConfig().getModelId().isEmpty());
 
-        // if space type is provided and legacy mappings is hit
-        xContentBuilder = XContentFactory.jsonBuilder()
-            .startObject()
-            .field(TYPE_FIELD_NAME, KNN_VECTOR_TYPE)
-            .field(DIMENSION_FIELD_NAME, TEST_DIMENSION)
-            .field(KNNConstants.TOP_LEVEL_PARAMETER_SPACE_TYPE, topLevelSpaceType.getValue())
-            .endObject();
-        builder = (KNNVectorFieldMapper.Builder) typeParser.parse(
-            "test-field-name-1",
-            xContentBuilderToMap(xContentBuilder),
-            buildParserContext("test", settings)
-        );
+        // mock useKNNMethodContextFromLegacy to simulate index ix created before 2_18
+        try (MockedStatic<KNNVectorFieldMapper> utilMockedStatic = Mockito.mockStatic(KNNVectorFieldMapper.class)) {
+            utilMockedStatic.when(() -> KNNVectorFieldMapper.useKNNMethodContextFromLegacy(any(), any())).thenReturn(true);
+            // if space type is provided and legacy mappings is hit
+            xContentBuilder = XContentFactory.jsonBuilder()
+                .startObject()
+                .field(TYPE_FIELD_NAME, KNN_VECTOR_TYPE)
+                .field(DIMENSION_FIELD_NAME, TEST_DIMENSION)
+                .field(KNNConstants.TOP_LEVEL_PARAMETER_SPACE_TYPE, topLevelSpaceType.getValue())
+                .endObject();
+            builder = (KNNVectorFieldMapper.Builder) typeParser.parse(
+                "test-field-name-1",
+                xContentBuilderToMap(xContentBuilder),
+                buildParserContext("test", settings)
+            );
 
-        builderContext = new Mapper.BuilderContext(settings, new ContentPath());
-        knnVectorFieldMapper = builder.build(builderContext);
-        assertTrue(knnVectorFieldMapper instanceof MethodFieldMapper);
-        assertTrue(knnVectorFieldMapper.fieldType().getKnnMappingConfig().getKnnMethodContext().isPresent());
-        assertEquals(topLevelSpaceType, knnVectorFieldMapper.fieldType().getKnnMappingConfig().getKnnMethodContext().get().getSpaceType());
-        // this check ensures that legacy mapping is hit, as in legacy mapping we pick M from index settings
-        assertEquals(
-            mForSetting,
-            knnVectorFieldMapper.fieldType()
-                .getKnnMappingConfig()
-                .getKnnMethodContext()
-                .get()
-                .getMethodComponentContext()
-                .getParameters()
-                .get(METHOD_PARAMETER_M)
-        );
-        assertTrue(knnVectorFieldMapper.fieldType().getKnnMappingConfig().getModelId().isEmpty());
+            builderContext = new Mapper.BuilderContext(settings, new ContentPath());
+            knnVectorFieldMapper = builder.build(builderContext);
+            assertTrue(knnVectorFieldMapper instanceof MethodFieldMapper);
+            assertTrue(knnVectorFieldMapper.fieldType().getKnnMappingConfig().getKnnMethodContext().isPresent());
+            assertEquals(
+                topLevelSpaceType,
+                knnVectorFieldMapper.fieldType().getKnnMappingConfig().getKnnMethodContext().get().getSpaceType()
+            );
+            // this check ensures that legacy mapping is hit, as in legacy mapping we pick M from index settings
+            assertEquals(
+                mForSetting,
+                knnVectorFieldMapper.fieldType()
+                    .getKnnMappingConfig()
+                    .getKnnMethodContext()
+                    .get()
+                    .getMethodComponentContext()
+                    .getParameters()
+                    .get(METHOD_PARAMETER_M)
+            );
+            assertTrue(knnVectorFieldMapper.fieldType().getKnnMappingConfig().getModelId().isEmpty());
+        }
     }
 
     public void testTypeParser_withSpaceTypeAndMode_thenSuccess() throws IOException {
@@ -1614,7 +1622,7 @@ public void testBuilder_whenBinaryWithLegacyKNNDisabled_thenValid() {
         assertTrue(knnVectorFieldMapper instanceof FlatVectorFieldMapper);
     }
 
-    public void testTypeParser_whenBinaryWithLegacyKNNEnabled_thenException() throws IOException {
+    public void testTypeParser_whenBinaryWithLegacyKNNEnabled_thenValid() throws IOException {
         // Check legacy is picked up if model context and method context are not set
         ModelDao modelDao = mock(ModelDao.class);
         KNNVectorFieldMapper.TypeParser typeParser = new KNNVectorFieldMapper.TypeParser(() -> modelDao);
@@ -1631,11 +1639,12 @@ public void testTypeParser_whenBinaryWithLegacyKNNEnabled_thenException() throws
             .field(VECTOR_DATA_TYPE_FIELD, VectorDataType.BINARY.getValue())
             .endObject();
 
-        Exception ex = expectThrows(Exception.class, () -> {
-            typeParser.parse(fieldName, xContentBuilderToMap(xContentBuilder), buildParserContext(indexName, settings));
-        });
-
-        assertTrue(ex.getMessage(), ex.getMessage().contains("does not support space type"));
+        final KNNVectorFieldMapper.Builder builder = (KNNVectorFieldMapper.Builder) typeParser.parse(
+            fieldName,
+            xContentBuilderToMap(xContentBuilder),
+            buildParserContext(indexName, settings)
+        );
+        assertEquals(SpaceType.HAMMING, builder.getOriginalParameters().getResolvedKnnMethodContext().getSpaceType());
     }
 
     public void testBuild_whenInvalidCharsInFieldName_thenThrowException() {
@@ -1661,7 +1670,7 @@ public void testTypeParser_whenModeAndCompressionAreSet_thenHandle() throws IOEx
         ModelDao modelDao = mock(ModelDao.class);
         KNNVectorFieldMapper.TypeParser typeParser = new KNNVectorFieldMapper.TypeParser(() -> modelDao);
 
-        // Default to nmslib and ensure legacy is in use
+        // Default to faiss and ensure legacy is in use
         XContentBuilder xContentBuilder = XContentFactory.jsonBuilder()
             .startObject()
             .field(TYPE_FIELD_NAME, KNN_VECTOR_TYPE)
@@ -1676,7 +1685,7 @@ public void testTypeParser_whenModeAndCompressionAreSet_thenHandle() throws IOEx
         assertTrue(builder.getOriginalParameters().isLegacyMapping());
         validateBuilderAfterParsing(
             builder,
-            KNNEngine.NMSLIB,
+            KNNEngine.DEFAULT,
             SpaceType.L2,
             VectorDataType.FLOAT,
             CompressionLevel.x1,
diff --git a/src/test/java/org/opensearch/knn/index/query/KNNWeightTests.java b/src/test/java/org/opensearch/knn/index/query/KNNWeightTests.java
index 482e7e0cb..511895026 100644
--- a/src/test/java/org/opensearch/knn/index/query/KNNWeightTests.java
+++ b/src/test/java/org/opensearch/knn/index/query/KNNWeightTests.java
@@ -108,6 +108,7 @@ public class KNNWeightTests extends KNNTestCase {
     private static final int K = 5;
     private static final Set<String> SEGMENT_FILES_NMSLIB = Set.of("_0.cfe", "_0_2011_target_field.hnswc");
     private static final Set<String> SEGMENT_FILES_FAISS = Set.of("_0.cfe", "_0_2011_target_field.faissc");
+    private static final Set<String> SEGMENT_FILES_DEFAULT = SEGMENT_FILES_FAISS;
     private static final Set<String> SEGMENT_MULTI_FIELD_FILES_FAISS = Set.of(
         "_0.cfe",
         "_0_2011_target_field.faissc",
@@ -174,7 +175,11 @@ public void tearDownAfterTest() {
     @SneakyThrows
     public void testQueryResultScoreNmslib() {
         for (SpaceType space : List.of(SpaceType.L2, SpaceType.L1, SpaceType.COSINESIMIL, SpaceType.INNER_PRODUCT, SpaceType.LINF)) {
-            testQueryScore(space::scoreTranslation, SEGMENT_FILES_NMSLIB, Map.of(SPACE_TYPE, space.getValue()));
+            testQueryScore(
+                space::scoreTranslation,
+                SEGMENT_FILES_NMSLIB,
+                Map.of(SPACE_TYPE, space.getValue(), KNN_ENGINE, KNNEngine.NMSLIB.getName())
+            );
         }
     }
 
@@ -398,7 +403,7 @@ public void testEmptyQueryResults() {
             Map.of(),
             Sort.RELEVANCE
         );
-        segmentInfo.setFiles(SEGMENT_FILES_NMSLIB);
+        segmentInfo.setFiles(SEGMENT_FILES_DEFAULT);
         final SegmentCommitInfo segmentCommitInfo = new SegmentCommitInfo(segmentInfo, 0, 0, 0, 0, 0, new byte[StringHelper.ID_LENGTH]);
         when(reader.getSegmentInfo()).thenReturn(segmentCommitInfo);
 
diff --git a/src/test/java/org/opensearch/knn/jni/JNIServiceTests.java b/src/test/java/org/opensearch/knn/jni/JNIServiceTests.java
index f6d118092..2a5d6cbc6 100644
--- a/src/test/java/org/opensearch/knn/jni/JNIServiceTests.java
+++ b/src/test/java/org/opensearch/knn/jni/JNIServiceTests.java
@@ -64,6 +64,7 @@
 import static org.opensearch.knn.common.KNNConstants.METHOD_PARAMETER_SPACE_TYPE;
 import static org.opensearch.knn.common.KNNConstants.NAME;
 import static org.opensearch.knn.common.KNNConstants.PARAMETERS;
+import static org.opensearch.knn.index.engine.KNNEngine.NMSLIB;
 
 public class JNIServiceTests extends KNNTestCase {
     static final int FP16_MAX = 65504;
@@ -118,7 +119,7 @@ public void testCreateIndex_nmslib_invalid_noSpaceType() {
                 testData.indexData.getDimension(),
                 "something",
                 Collections.emptyMap(),
-                KNNEngine.NMSLIB
+                NMSLIB
             )
         );
     }
@@ -137,7 +138,7 @@ public void testCreateIndex_nmslib_invalid_vectorDocIDMismatch() throws IOExcept
                 vectors1[0].length,
                 tmpFile1.toAbsolutePath().toString(),
                 ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue()),
-                KNNEngine.NMSLIB
+                NMSLIB
             )
         );
 
@@ -153,7 +154,7 @@ public void testCreateIndex_nmslib_invalid_vectorDocIDMismatch() throws IOExcept
                 vectors2[0].length,
                 tmpFile2.toAbsolutePath().toString(),
                 ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue()),
-                KNNEngine.NMSLIB
+                NMSLIB
             )
         );
     }
@@ -172,7 +173,7 @@ public void testCreateIndex_nmslib_invalid_nullArgument() throws IOException {
                 0,
                 tmpFile.toAbsolutePath().toString(),
                 ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue()),
-                KNNEngine.NMSLIB
+                NMSLIB
             )
         );
 
@@ -184,7 +185,7 @@ public void testCreateIndex_nmslib_invalid_nullArgument() throws IOException {
                 0,
                 tmpFile.toAbsolutePath().toString(),
                 ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue()),
-                KNNEngine.NMSLIB
+                NMSLIB
             )
         );
 
@@ -196,13 +197,13 @@ public void testCreateIndex_nmslib_invalid_nullArgument() throws IOException {
                 0,
                 null,
                 ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue()),
-                KNNEngine.NMSLIB
+                NMSLIB
             )
         );
 
         expectThrows(
             Exception.class,
-            () -> TestUtils.createIndex(docIds, memoryAddress, 0, tmpFile.toAbsolutePath().toString(), null, KNNEngine.NMSLIB)
+            () -> TestUtils.createIndex(docIds, memoryAddress, 0, tmpFile.toAbsolutePath().toString(), null, NMSLIB)
         );
 
         expectThrows(
@@ -232,7 +233,7 @@ public void testCreateIndex_nmslib_invalid_badSpace() throws IOException {
                 vectors[0].length,
                 tmpFile.toAbsolutePath().toString(),
                 ImmutableMap.of(KNNConstants.SPACE_TYPE, "invalid"),
-                KNNEngine.NMSLIB
+                NMSLIB
             )
         );
     }
@@ -258,7 +259,7 @@ public void testCreateIndex_nmslib_invalid_badParameterType() throws IOException
                 vectors[0].length,
                 tmpFile.toAbsolutePath().toString(),
                 ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue(), KNNConstants.PARAMETERS, parametersMap),
-                KNNEngine.NMSLIB
+                NMSLIB
             )
         );
     }
@@ -278,7 +279,7 @@ public void testCreateIndex_nmslib_valid() throws IOException {
                 testData.indexData.getDimension(),
                 tmpFile.toAbsolutePath().toString(),
                 ImmutableMap.of(KNNConstants.SPACE_TYPE, spaceType.getValue()),
-                KNNEngine.NMSLIB
+                NMSLIB
             );
             assertTrue(tmpFile.toFile().length() > 0);
 
@@ -297,7 +298,7 @@ public void testCreateIndex_nmslib_valid() throws IOException {
                     KNNConstants.METHOD_PARAMETER_M,
                     12
                 ),
-                KNNEngine.NMSLIB
+                NMSLIB
             );
             assertTrue(tmpFile.toFile().length() > 0);
         }
@@ -698,20 +699,17 @@ public void testLoadIndex_invalidEngine() {
     }
 
     public void testLoadIndex_nmslib_invalid_badSpaceType() {
-        expectThrows(
-            Exception.class,
-            () -> JNIService.loadIndex("test", ImmutableMap.of(KNNConstants.SPACE_TYPE, "invalid"), KNNEngine.NMSLIB)
-        );
+        expectThrows(Exception.class, () -> JNIService.loadIndex("test", ImmutableMap.of(KNNConstants.SPACE_TYPE, "invalid"), NMSLIB));
     }
 
     public void testLoadIndex_nmslib_invalid_noSpaceType() {
-        expectThrows(Exception.class, () -> JNIService.loadIndex("test", Collections.emptyMap(), KNNEngine.NMSLIB));
+        expectThrows(Exception.class, () -> JNIService.loadIndex("test", Collections.emptyMap(), NMSLIB));
     }
 
     public void testLoadIndex_nmslib_invalid_fileDoesNotExist() {
         expectThrows(
             Exception.class,
-            () -> JNIService.loadIndex("invalid", ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue()), KNNEngine.NMSLIB)
+            () -> JNIService.loadIndex("invalid", ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue()), NMSLIB)
         );
     }
 
@@ -722,7 +720,7 @@ public void testLoadIndex_nmslib_invalid_badFile() throws IOException {
             () -> JNIService.loadIndex(
                 tmpFile.toAbsolutePath().toString(),
                 ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue()),
-                KNNEngine.NMSLIB
+                NMSLIB
             )
         );
     }
@@ -737,14 +735,14 @@ public void testLoadIndex_nmslib_valid() throws IOException {
             testData.indexData.getDimension(),
             tmpFile.toAbsolutePath().toString(),
             ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue()),
-            KNNEngine.NMSLIB
+            NMSLIB
         );
         assertTrue(tmpFile.toFile().length() > 0);
 
         long pointer = JNIService.loadIndex(
             tmpFile.toAbsolutePath().toString(),
             ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue()),
-            KNNEngine.NMSLIB
+            NMSLIB
         );
         assertNotEquals(0, pointer);
     }
@@ -757,8 +755,8 @@ public void testLoadIndex_nmslib_valid_with_stream() throws IOException {
             testData.loadDataToMemoryAddress(),
             testData.indexData.getDimension(),
             tmpFile.toAbsolutePath().toString(),
-            ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue()),
-            KNNEngine.NMSLIB
+            ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue(), KNN_ENGINE, NMSLIB),
+            NMSLIB
         );
         assertTrue(tmpFile.toFile().length() > 0);
 
@@ -767,7 +765,7 @@ public void testLoadIndex_nmslib_valid_with_stream() throws IOException {
                 long pointer = JNIService.loadIndex(
                     new IndexInputWithBuffer(indexInput),
                     ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue()),
-                    KNNEngine.NMSLIB
+                    NMSLIB
                 );
                 assertNotEquals(0, pointer);
             }
@@ -815,7 +813,7 @@ public void testQueryIndex_invalidEngine() {
 
     public void testQueryIndex_nmslib_invalid_badPointer() {
 
-        expectThrows(Exception.class, () -> JNIService.queryIndex(0L, new float[] {}, 0, null, KNNEngine.NMSLIB, null, 0, null));
+        expectThrows(Exception.class, () -> JNIService.queryIndex(0L, new float[] {}, 0, null, NMSLIB, null, 0, null));
     }
 
     public void testQueryIndex_nmslib_invalid_nullQueryVector() throws IOException {
@@ -828,18 +826,18 @@ public void testQueryIndex_nmslib_invalid_nullQueryVector() throws IOException {
             testData.indexData.getDimension(),
             tmpFile.toAbsolutePath().toString(),
             ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue()),
-            KNNEngine.NMSLIB
+            NMSLIB
         );
         assertTrue(tmpFile.toFile().length() > 0);
 
         long pointer = JNIService.loadIndex(
             tmpFile.toAbsolutePath().toString(),
             ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue()),
-            KNNEngine.NMSLIB
+            NMSLIB
         );
         assertNotEquals(0, pointer);
 
-        expectThrows(Exception.class, () -> JNIService.queryIndex(pointer, null, 10, null, KNNEngine.NMSLIB, null, 0, null));
+        expectThrows(Exception.class, () -> JNIService.queryIndex(pointer, null, 10, null, NMSLIB, null, 0, null));
     }
 
     public void testQueryIndex_nmslib_valid() throws IOException {
@@ -858,19 +856,19 @@ public void testQueryIndex_nmslib_valid() throws IOException {
                 testData.indexData.getDimension(),
                 tmpFile.toAbsolutePath().toString(),
                 ImmutableMap.of(KNNConstants.SPACE_TYPE, spaceType.getValue()),
-                KNNEngine.NMSLIB
+                NMSLIB
             );
             assertTrue(tmpFile.toFile().length() > 0);
 
             long pointer = JNIService.loadIndex(
                 tmpFile.toAbsolutePath().toString(),
                 ImmutableMap.of(KNNConstants.SPACE_TYPE, spaceType.getValue()),
-                KNNEngine.NMSLIB
+                NMSLIB
             );
             assertNotEquals(0, pointer);
 
             for (float[] query : testData.queries) {
-                KNNQueryResult[] results = JNIService.queryIndex(pointer, query, k, null, KNNEngine.NMSLIB, null, 0, null);
+                KNNQueryResult[] results = JNIService.queryIndex(pointer, query, k, null, NMSLIB, null, 0, null);
                 assertEquals(k, results.length);
             }
         }
@@ -1284,18 +1282,18 @@ public void testFree_nmslib_valid() throws IOException {
             testData.indexData.getDimension(),
             tmpFile.toAbsolutePath().toString(),
             ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue()),
-            KNNEngine.NMSLIB
+            NMSLIB
         );
         assertTrue(tmpFile.toFile().length() > 0);
 
         long pointer = JNIService.loadIndex(
             tmpFile.toAbsolutePath().toString(),
             ImmutableMap.of(KNNConstants.SPACE_TYPE, SpaceType.L2.getValue()),
-            KNNEngine.NMSLIB
+            NMSLIB
         );
         assertNotEquals(0, pointer);
 
-        JNIService.free(pointer, KNNEngine.NMSLIB);
+        JNIService.free(pointer, NMSLIB);
     }
 
     public void testFree_faiss_valid() throws IOException {
@@ -1550,7 +1548,7 @@ public void testIndexLoad_whenStateIsShared_thenSucceed() {
     @SneakyThrows
     public void testIsIndexIVFPQL2() {
         long dummyAddress = 0;
-        assertFalse(JNIService.isSharedIndexStateRequired(dummyAddress, KNNEngine.NMSLIB));
+        assertFalse(JNIService.isSharedIndexStateRequired(dummyAddress, NMSLIB));
 
         String faissIVFPQL2Index = createFaissIVFPQIndex(16, 16, 4, SpaceType.L2);
         long faissIVFPQL2Address = JNIService.loadIndex(faissIVFPQL2Index, Collections.emptyMap(), KNNEngine.FAISS);
@@ -1571,9 +1569,9 @@ public void testIsIndexIVFPQL2() {
     @SneakyThrows
     public void testFunctionsUnsupportedForEngine_whenEngineUnsupported_thenThrowIllegalArgumentException() {
         int dummyAddress = 0;
-        expectThrows(IllegalArgumentException.class, () -> JNIService.initSharedIndexState(dummyAddress, KNNEngine.NMSLIB));
-        expectThrows(IllegalArgumentException.class, () -> JNIService.setSharedIndexState(dummyAddress, dummyAddress, KNNEngine.NMSLIB));
-        expectThrows(IllegalArgumentException.class, () -> JNIService.freeSharedIndexState(dummyAddress, KNNEngine.NMSLIB));
+        expectThrows(IllegalArgumentException.class, () -> JNIService.initSharedIndexState(dummyAddress, NMSLIB));
+        expectThrows(IllegalArgumentException.class, () -> JNIService.setSharedIndexState(dummyAddress, dummyAddress, NMSLIB));
+        expectThrows(IllegalArgumentException.class, () -> JNIService.freeSharedIndexState(dummyAddress, NMSLIB));
     }
 
     private void assertQueryResultsMatch(float[][] testQueries, int k, List<Long> indexAddresses) {
diff --git a/src/test/java/org/opensearch/knn/plugin/transport/GetModelResponseTests.java b/src/test/java/org/opensearch/knn/plugin/transport/GetModelResponseTests.java
index 3bf5f302c..771b07edd 100644
--- a/src/test/java/org/opensearch/knn/plugin/transport/GetModelResponseTests.java
+++ b/src/test/java/org/opensearch/knn/plugin/transport/GetModelResponseTests.java
@@ -30,6 +30,7 @@
 import org.opensearch.knn.indices.ModelState;
 
 import java.io.IOException;
+import java.util.Locale;
 
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.mockStatic;
@@ -76,7 +77,9 @@ public void testXContent() throws IOException {
             Model model = new Model(getModelMetadata(ModelState.CREATED), testModelBlob, modelId);
             GetModelResponse getModelResponse = new GetModelResponse(model);
             String expectedResponseString = String.format(
-                "{\"model_id\":\"test-model\",\"model_blob\":\"aGVsbG8=\",\"state\":\"created\",\"timestamp\":\"2021-03-27 10:15:30 AM +05:30\",\"description\":\"test model\",\"error\":\"\",\"space_type\":\"l2\",\"dimension\":4,\"engine\":\"nmslib\",\"training_node_assignment\":\"\",\"model_definition\":{\"name\":\"\",\"parameters\":{}},\"data_type\":\"float\",\"model_version\":\"%s\"}",
+                Locale.ROOT,
+                "{\"model_id\":\"test-model\",\"model_blob\":\"aGVsbG8=\",\"state\":\"created\",\"timestamp\":\"2021-03-27 10:15:30 AM +05:30\",\"description\":\"test model\",\"error\":\"\",\"space_type\":\"l2\",\"dimension\":4,\"engine\":\"%s\",\"training_node_assignment\":\"\",\"model_definition\":{\"name\":\"\",\"parameters\":{}},\"data_type\":\"float\",\"model_version\":\"%s\"}",
+                KNNEngine.DEFAULT.getName(),
                 Version.CURRENT.toString()
             );
             XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
@@ -94,7 +97,9 @@ public void testXContentWithNoModelBlob() throws IOException {
             Model model = new Model(getModelMetadata(ModelState.FAILED), null, modelId);
             GetModelResponse getModelResponse = new GetModelResponse(model);
             String expectedResponseString = String.format(
-                "{\"model_id\":\"test-model\",\"model_blob\":\"\",\"state\":\"failed\",\"timestamp\":\"2021-03-27 10:15:30 AM +05:30\",\"description\":\"test model\",\"error\":\"\",\"space_type\":\"l2\",\"dimension\":4,\"engine\":\"nmslib\",\"training_node_assignment\":\"\",\"model_definition\":{\"name\":\"\",\"parameters\":{}},\"data_type\":\"float\",\"model_version\":\"%s\"}",
+                Locale.ROOT,
+                "{\"model_id\":\"test-model\",\"model_blob\":\"\",\"state\":\"failed\",\"timestamp\":\"2021-03-27 10:15:30 AM +05:30\",\"description\":\"test model\",\"error\":\"\",\"space_type\":\"l2\",\"dimension\":4,\"engine\":\"%s\",\"training_node_assignment\":\"\",\"model_definition\":{\"name\":\"\",\"parameters\":{}},\"data_type\":\"float\",\"model_version\":\"%s\"}",
+                KNNEngine.DEFAULT.getName(),
                 Version.CURRENT.toString()
             );
             XContentBuilder xContentBuilder = MediaTypeRegistry.contentBuilder(XContentType.JSON);
diff --git a/src/test/java/org/opensearch/knn/plugin/transport/TrainingModelRequestTests.java b/src/test/java/org/opensearch/knn/plugin/transport/TrainingModelRequestTests.java
index 2c423e0ef..6fd399434 100644
--- a/src/test/java/org/opensearch/knn/plugin/transport/TrainingModelRequestTests.java
+++ b/src/test/java/org/opensearch/knn/plugin/transport/TrainingModelRequestTests.java
@@ -46,6 +46,7 @@
 
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
+import static org.opensearch.knn.common.KNNConstants.METHOD_HNSW;
 
 public class TrainingModelRequestTests extends KNNTestCase {
 
@@ -290,11 +291,14 @@ public void testValidation_invalid_invalidMethodContext() {
         String trainingIndex = "test-training-index";
         String trainingField = "test-training-field";
 
+        MethodComponentContext methodComponentContext = new MethodComponentContext(METHOD_HNSW, Collections.emptyMap());
+        final KNNMethodContext knnMethodContext = new KNNMethodContext(KNNEngine.NMSLIB, SpaceType.DEFAULT, methodComponentContext);
+
         ValidationException validationException = expectThrows(
             ValidationException.class,
             () -> new TrainingModelRequest(
                 modelId,
-                getDefaultKNNMethodContext(),
+                knnMethodContext,
                 dimension,
                 trainingIndex,
                 trainingField,