diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultIndexOperations.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultIndexOperations.java
index 826d513a9..33b1aea65 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultIndexOperations.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultIndexOperations.java
@@ -20,6 +20,7 @@ import java.util.Collection;
 import java.util.List;
 
 import org.bson.Document;
+
 import org.springframework.dao.DataAccessException;
 import org.springframework.data.mongodb.MongoDatabaseFactory;
 import org.springframework.data.mongodb.UncategorizedMongoDbException;
@@ -54,7 +55,7 @@ public class DefaultIndexOperations implements IndexOperations {
 	private final QueryMapper mapper;
 	private final @Nullable Class<?> type;
 
-	private MongoOperations mongoOperations;
+	private final MongoOperations mongoOperations;
 
 	/**
 	 * Creates a new {@link DefaultIndexOperations}.
@@ -115,7 +116,7 @@ public class DefaultIndexOperations implements IndexOperations {
 	}
 
 	@Override
-	public String ensureIndex(final IndexDefinition indexDefinition) {
+	public String ensureIndex(IndexDefinition indexDefinition) {
 
 		return execute(collection -> {
 
@@ -149,7 +150,8 @@ public class DefaultIndexOperations implements IndexOperations {
 		return null;
 	}
 
-	public void dropIndex(final String name) {
+	@Override
+	public void dropIndex(String name) {
 
 		execute(collection -> {
 			collection.dropIndex(name);
@@ -167,15 +169,18 @@ public class DefaultIndexOperations implements IndexOperations {
 		Document result = mongoOperations
 				.execute(db -> db.runCommand(new Document("collMod", collectionName).append("index", indexOptions)));
 
-		if(NumberUtils.convertNumberToTargetClass(result.get("ok", (Number) 0), Integer.class) != 1) {
-			throw new UncategorizedMongoDbException("Index '%s' could not be modified. Response was %s".formatted(name, result.toJson()), null);
+		if (NumberUtils.convertNumberToTargetClass(result.get("ok", (Number) 0), Integer.class) != 1) {
+			throw new UncategorizedMongoDbException(
+					"Index '%s' could not be modified. Response was %s".formatted(name, result.toJson()), null);
 		}
 	}
 
+	@Override
 	public void dropAllIndexes() {
 		dropIndex("*");
 	}
 
+	@Override
 	public List<IndexInfo> getIndexInfo() {
 
 		return execute(new CollectionCallback<List<IndexInfo>>() {
@@ -224,7 +229,8 @@ public class DefaultIndexOperations implements IndexOperations {
 				mapper.getMappedSort((Document) sourceOptions.get(PARTIAL_FILTER_EXPRESSION_KEY), entity));
 	}
 
-	private static IndexOptions addDefaultCollationIfRequired(IndexOptions ops, MongoPersistentEntity<?> entity) {
+	private static IndexOptions addDefaultCollationIfRequired(IndexOptions ops,
+			@Nullable MongoPersistentEntity<?> entity) {
 
 		if (ops.getCollation() != null || entity == null || !entity.hasCollation()) {
 			return ops;
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultReactiveIndexOperations.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultReactiveIndexOperations.java
index 548d3e086..63f4c1d9a 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultReactiveIndexOperations.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultReactiveIndexOperations.java
@@ -116,8 +116,9 @@ public class DefaultReactiveIndexOperations implements ReactiveIndexOperations {
 
 			return Flux.from(db.runCommand(new Document("collMod", collectionName).append("index", indexOptions)))
 					.doOnNext(result -> {
-						if(NumberUtils.convertNumberToTargetClass(result.get("ok", (Number) 0), Integer.class) != 1) {
-							throw new UncategorizedMongoDbException("Index '%s' could not be modified. Response was %s".formatted(name, result.toJson()), null);
+						if (NumberUtils.convertNumberToTargetClass(result.get("ok", (Number) 0), Integer.class) != 1) {
+							throw new UncategorizedMongoDbException(
+									"Index '%s' could not be modified. Response was %s".formatted(name, result.toJson()), null);
 						}
 					});
 		}).then();
@@ -134,14 +135,17 @@ public class DefaultReactiveIndexOperations implements ReactiveIndexOperations {
 				.orElse(null);
 	}
 
-	public Mono<Void> dropIndex(final String name) {
+	@Override
+	public Mono<Void> dropIndex(String name) {
 		return mongoOperations.execute(collectionName, collection -> collection.dropIndex(name)).then();
 	}
 
+	@Override
 	public Mono<Void> dropAllIndexes() {
 		return dropIndex("*");
 	}
 
+	@Override
 	public Flux<IndexInfo> getIndexInfo() {
 
 		return mongoOperations.execute(collectionName, collection -> collection.listIndexes(Document.class)) //
@@ -160,7 +164,8 @@ public class DefaultReactiveIndexOperations implements ReactiveIndexOperations {
 				queryMapper.getMappedObject((Document) sourceOptions.get(PARTIAL_FILTER_EXPRESSION_KEY), entity));
 	}
 
-	private static IndexOptions addDefaultCollationIfRequired(IndexOptions ops, MongoPersistentEntity<?> entity) {
+	private static IndexOptions addDefaultCollationIfRequired(IndexOptions ops,
+			@Nullable MongoPersistentEntity<?> entity) {
 
 		if (ops.getCollation() != null || entity == null || !entity.hasCollation()) {
 			return ops;
diff --git a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultScriptOperations.java b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultScriptOperations.java
index 127a12743..2fadefdae 100644
--- a/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultScriptOperations.java
+++ b/spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultScriptOperations.java
@@ -85,7 +85,7 @@ class DefaultScriptOperations implements ScriptOperations {
 	}
 
 	@Override
-	public Object execute(final ExecutableMongoScript script, final Object... args) {
+	public Object execute(ExecutableMongoScript script, Object... args) {
 
 		Assert.notNull(script, "Script must not be null");
 
@@ -104,7 +104,7 @@ class DefaultScriptOperations implements ScriptOperations {
 	}
 
 	@Override
-	public Object call(final String scriptName, final Object... args) {
+	public Object call(String scriptName, Object... args) {
 
 		Assert.hasText(scriptName, "ScriptName must not be null or empty");