diff --git a/java-client/src/main/java/co/elastic/clients/elasticsearch/indices/CreateFromRequest.java b/java-client/src/main/java/co/elastic/clients/elasticsearch/indices/CreateFromRequest.java
index 083d44223..9d3a24d1a 100644
--- a/java-client/src/main/java/co/elastic/clients/elasticsearch/indices/CreateFromRequest.java
+++ b/java-client/src/main/java/co/elastic/clients/elasticsearch/indices/CreateFromRequest.java
@@ -74,6 +74,7 @@ public class CreateFromRequest extends RequestBase implements JsonpSerializable
 
 	private final String source;
 
+	@Nullable
 	private final CreateFrom createFrom;
 
 	// ---------------------------------------------------------------------------------------------
@@ -82,7 +83,7 @@ private CreateFromRequest(Builder builder) {
 
 		this.dest = ApiTypeHelper.requireNonNull(builder.dest, this, "dest");
 		this.source = ApiTypeHelper.requireNonNull(builder.source, this, "source");
-		this.createFrom = ApiTypeHelper.requireNonNull(builder.createFrom, this, "createFrom");
+		this.createFrom = builder.createFrom;
 
 	}
 
@@ -109,8 +110,9 @@ public final String source() {
 	}
 
 	/**
-	 * Required - Request body.
+	 * Request body.
 	 */
+	@Nullable
 	public final CreateFrom createFrom() {
 		return this.createFrom;
 	}
@@ -136,6 +138,7 @@ public static class Builder extends RequestBase.AbstractBuilder<Builder>
 
 		private String source;
 
+		@Nullable
 		private CreateFrom createFrom;
 
 		public Builder() {
@@ -167,15 +170,15 @@ public final Builder source(String value) {
 		}
 
 		/**
-		 * Required - Request body.
+		 * Request body.
 		 */
-		public final Builder createFrom(CreateFrom value) {
+		public final Builder createFrom(@Nullable CreateFrom value) {
 			this.createFrom = value;
 			return this;
 		}
 
 		/**
-		 * Required - Request body.
+		 * Request body.
 		 */
 		public final Builder createFrom(Function<CreateFrom.Builder, ObjectBuilder<CreateFrom>> fn) {
 			return this.createFrom(fn.apply(new CreateFrom.Builder()).build());
diff --git a/java-client/src/main/java/co/elastic/clients/elasticsearch/indices/SimulateIndexTemplateRequest.java b/java-client/src/main/java/co/elastic/clients/elasticsearch/indices/SimulateIndexTemplateRequest.java
index a8de6425b..82a9aef0d 100644
--- a/java-client/src/main/java/co/elastic/clients/elasticsearch/indices/SimulateIndexTemplateRequest.java
+++ b/java-client/src/main/java/co/elastic/clients/elasticsearch/indices/SimulateIndexTemplateRequest.java
@@ -85,6 +85,7 @@ public class SimulateIndexTemplateRequest extends RequestBase implements JsonpSe
 
 	private final String name;
 
+	@Nullable
 	private final IndexTemplate indexTemplate;
 
 	// ---------------------------------------------------------------------------------------------
@@ -96,7 +97,7 @@ private SimulateIndexTemplateRequest(Builder builder) {
 		this.includeDefaults = builder.includeDefaults;
 		this.masterTimeout = builder.masterTimeout;
 		this.name = ApiTypeHelper.requireNonNull(builder.name, this, "name");
-		this.indexTemplate = ApiTypeHelper.requireNonNull(builder.indexTemplate, this, "indexTemplate");
+		this.indexTemplate = builder.indexTemplate;
 
 	}
 
@@ -157,8 +158,9 @@ public final String name() {
 	}
 
 	/**
-	 * Required - Request body.
+	 * Request body.
 	 */
+	@Nullable
 	public final IndexTemplate indexTemplate() {
 		return this.indexTemplate;
 	}
@@ -194,6 +196,7 @@ public static class Builder extends RequestBase.AbstractBuilder<Builder>
 
 		private String name;
 
+		@Nullable
 		private IndexTemplate indexTemplate;
 
 		public Builder() {
@@ -271,15 +274,15 @@ public final Builder name(String value) {
 		}
 
 		/**
-		 * Required - Request body.
+		 * Request body.
 		 */
-		public final Builder indexTemplate(IndexTemplate value) {
+		public final Builder indexTemplate(@Nullable IndexTemplate value) {
 			this.indexTemplate = value;
 			return this;
 		}
 
 		/**
-		 * Required - Request body.
+		 * Request body.
 		 */
 		public final Builder indexTemplate(Function<IndexTemplate.Builder, ObjectBuilder<IndexTemplate>> fn) {
 			return this.indexTemplate(fn.apply(new IndexTemplate.Builder()).build());