Polishing contribution

Closes gh-32799

spring-web/src/main/java/org/springframework/http/client/reactive/JdkClientHttpRequest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -37,6 +37,7 @@ import org.springframework.http.HttpCookie;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.util.Assert;
+import org.springframework.util.MultiValueMap;
 
 /**
  * {@link ClientHttpRequest} for the Java {@link HttpClient}.
@@ -108,7 +109,11 @@ class JdkClientHttpRequest extends AbstractClientHttpRequest {
 
 	@Override
 	protected void applyCookies() {
-		this.builder.header(HttpHeaders.COOKIE, getCookies().values().stream()
+		MultiValueMap<String, HttpCookie> cookies = getCookies();
+		if (cookies.isEmpty()) {
+			return;
+		}
+		this.builder.header(HttpHeaders.COOKIE, cookies.values().stream()
 				.flatMap(List::stream).map(HttpCookie::toString).collect(Collectors.joining(";")));
 	}