diff --git a/java-client/src/main/java/co/elastic/clients/elasticsearch/async_search/SubmitRequest.java b/java-client/src/main/java/co/elastic/clients/elasticsearch/async_search/SubmitRequest.java
index 9c8b9319e..e90d5fddf 100644
--- a/java-client/src/main/java/co/elastic/clients/elasticsearch/async_search/SubmitRequest.java
+++ b/java-client/src/main/java/co/elastic/clients/elasticsearch/async_search/SubmitRequest.java
@@ -1074,12 +1074,18 @@ protected void serializeInternal(JsonGenerator generator, JsonpMapper mapper) {
 		}
 		if (ApiTypeHelper.isDefined(this.storedFields)) {
 			generator.writeKey("stored_fields");
-			generator.writeStartArray();
-			for (String item0 : this.storedFields) {
-				generator.write(item0);
+			if (this.storedFields.size() == 1) {
+				String singleItem = this.storedFields.get(0);
+				generator.write(singleItem);
+
+			} else {
+				generator.writeStartArray();
+				for (String item0 : this.storedFields) {
+					generator.write(item0);
 
+				}
+				generator.writeEnd();
 			}
-			generator.writeEnd();
 
 		}
 		if (this.suggest != null) {
diff --git a/java-client/src/main/java/co/elastic/clients/elasticsearch/core/SearchRequest.java b/java-client/src/main/java/co/elastic/clients/elasticsearch/core/SearchRequest.java
index c3f6eb61b..bbb2b6de3 100644
--- a/java-client/src/main/java/co/elastic/clients/elasticsearch/core/SearchRequest.java
+++ b/java-client/src/main/java/co/elastic/clients/elasticsearch/core/SearchRequest.java
@@ -1060,12 +1060,18 @@ protected void serializeInternal(JsonGenerator generator, JsonpMapper mapper) {
 		}
 		if (ApiTypeHelper.isDefined(this.storedFields)) {
 			generator.writeKey("stored_fields");
-			generator.writeStartArray();
-			for (String item0 : this.storedFields) {
-				generator.write(item0);
+			if (this.storedFields.size() == 1) {
+				String singleItem = this.storedFields.get(0);
+				generator.write(singleItem);
+
+			} else {
+				generator.writeStartArray();
+				for (String item0 : this.storedFields) {
+					generator.write(item0);
 
+				}
+				generator.writeEnd();
 			}
-			generator.writeEnd();
 
 		}
 		if (this.suggest != null) {
diff --git a/java-client/src/main/java/co/elastic/clients/elasticsearch/core/search/Hit.java b/java-client/src/main/java/co/elastic/clients/elasticsearch/core/search/Hit.java
index f9b7efa07..58f753b26 100644
--- a/java-client/src/main/java/co/elastic/clients/elasticsearch/core/search/Hit.java
+++ b/java-client/src/main/java/co/elastic/clients/elasticsearch/core/search/Hit.java
@@ -72,6 +72,7 @@
 public class Hit<TDocument> implements JsonpSerializable {
 	private final String index;
 
+	@Nullable
 	private final String id;
 
 	@Nullable
@@ -127,7 +128,7 @@ public class Hit<TDocument> implements JsonpSerializable {
 	private Hit(Builder<TDocument> builder) {
 
 		this.index = ApiTypeHelper.requireNonNull(builder.index, this, "index");
-		this.id = ApiTypeHelper.requireNonNull(builder.id, this, "id");
+		this.id = builder.id;
 		this.score = builder.score;
 		this.type = builder.type;
 		this.explanation = builder.explanation;
@@ -161,8 +162,9 @@ public final String index() {
 	}
 
 	/**
-	 * Required - API name: {@code _id}
+	 * API name: {@code _id}
 	 */
+	@Nullable
 	public final String id() {
 		return this.id;
 	}
@@ -311,9 +313,11 @@ protected void serializeInternal(JsonGenerator generator, JsonpMapper mapper) {
 		generator.writeKey("_index");
 		generator.write(this.index);
 
-		generator.writeKey("_id");
-		generator.write(this.id);
+		if (this.id != null) {
+			generator.writeKey("_id");
+			generator.write(this.id);
 
+		}
 		if (this.score != null) {
 			generator.writeKey("_score");
 			generator.write(this.score);
@@ -458,6 +462,7 @@ public static class Builder<TDocument> extends WithJsonObjectBuilderBase<Builder
 				ObjectBuilder<Hit<TDocument>> {
 		private String index;
 
+		@Nullable
 		private String id;
 
 		@Nullable
@@ -523,9 +528,9 @@ public final Builder<TDocument> index(String value) {
 		}
 
 		/**
-		 * Required - API name: {@code _id}
+		 * API name: {@code _id}
 		 */
-		public final Builder<TDocument> id(String value) {
+		public final Builder<TDocument> id(@Nullable String value) {
 			this.id = value;
 			return this;
 		}
diff --git a/java-client/src/main/java/co/elastic/clients/elasticsearch/doc-files/api-spec.html b/java-client/src/main/java/co/elastic/clients/elasticsearch/doc-files/api-spec.html
index 4ec471f3a..51a56434f 100644
--- a/java-client/src/main/java/co/elastic/clients/elasticsearch/doc-files/api-spec.html
+++ b/java-client/src/main/java/co/elastic/clients/elasticsearch/doc-files/api-spec.html
@@ -2351,10 +2351,10 @@
         if (hash.length > 1) {
             hash = hash.substring(1);
         }
-        window.location = "https://github.com/elastic/elasticsearch-specification/tree/3458c5d2594e7ad33da1b128469faa09881bbead/specification/" + (paths[hash] || "");
+        window.location = "https://github.com/elastic/elasticsearch-specification/tree/60128dd705a0e7c7f4da6044f1c54ff6a86157eb/specification/" + (paths[hash] || "");
     </script>
 </head>
 <body>
-    Please see the <a href="https://github.com/elastic/elasticsearch-specification/tree/3458c5d2594e7ad33da1b128469faa09881bbead/specification/">Elasticsearch API specification</a>.
+    Please see the <a href="https://github.com/elastic/elasticsearch-specification/tree/60128dd705a0e7c7f4da6044f1c54ff6a86157eb/specification/">Elasticsearch API specification</a>.
 </body>
 </html>