From fc1ff88ede379eab3796b5645695c846d3c36180 Mon Sep 17 00:00:00 2001
From: Brian Clozel <brian.clozel@broadcom.com>
Date: Mon, 22 Dec 2025 15:34:41 +0100
Subject: [PATCH] Avoid duplicate flushes in String Http converter

Prior to this commit, the `StringHttpMessageConverter` would perform a
flush after writing the body, via `StreamUtils#copy`. This operation is
not needed as a flush is already performed by the abstract class.

Flush calls by HTTP message converters is being reconsidered altogether
in gh-35427, but we should first remove this extra operation.

Closes gh-36065
---
 .../http/converter/StringHttpMessageConverter.java             | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/spring-web/src/main/java/org/springframework/http/converter/StringHttpMessageConverter.java b/spring-web/src/main/java/org/springframework/http/converter/StringHttpMessageConverter.java
index 6e4aed4717a..5a9e81e90da 100644
--- a/spring-web/src/main/java/org/springframework/http/converter/StringHttpMessageConverter.java
+++ b/spring-web/src/main/java/org/springframework/http/converter/StringHttpMessageConverter.java
@@ -29,7 +29,6 @@ import org.springframework.http.HttpInputMessage;
 import org.springframework.http.HttpOutputMessage;
 import org.springframework.http.MediaType;
 import org.springframework.util.Assert;
-import org.springframework.util.StreamUtils;
 
 /**
  * Implementation of {@link HttpMessageConverter} that can read and write strings.
@@ -125,7 +124,7 @@ public class StringHttpMessageConverter extends AbstractHttpMessageConverter<Str
 			headers.setAcceptCharset(getAcceptedCharsets());
 		}
 		Charset charset = getContentTypeCharset(headers.getContentType());
-		StreamUtils.copy(str, charset, outputMessage.getBody());
+		outputMessage.getBody().write(str.getBytes(charset));
 	}