diff --git a/spring-core/src/main/java/org/springframework/core/io/buffer/DefaultDataBuffer.java b/spring-core/src/main/java/org/springframework/core/io/buffer/DefaultDataBuffer.java
index d1f5e9d0e35..be2155f3433 100644
--- a/spring-core/src/main/java/org/springframework/core/io/buffer/DefaultDataBuffer.java
+++ b/spring-core/src/main/java/org/springframework/core/io/buffer/DefaultDataBuffer.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
diff --git a/spring-core/src/testFixtures/java/org/springframework/core/testfixture/codec/AbstractEncoderTests.java b/spring-core/src/testFixtures/java/org/springframework/core/testfixture/codec/AbstractEncoderTests.java
index 74d930f67b4..106cc114e89 100644
--- a/spring-core/src/testFixtures/java/org/springframework/core/testfixture/codec/AbstractEncoderTests.java
+++ b/spring-core/src/testFixtures/java/org/springframework/core/testfixture/codec/AbstractEncoderTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
diff --git a/spring-core/src/testFixtures/java/org/springframework/core/testfixture/io/buffer/DataBufferTestUtils.java b/spring-core/src/testFixtures/java/org/springframework/core/testfixture/io/buffer/DataBufferTestUtils.java
index 12ab9ad8c6a..b1e96092f03 100644
--- a/spring-core/src/testFixtures/java/org/springframework/core/testfixture/io/buffer/DataBufferTestUtils.java
+++ b/spring-core/src/testFixtures/java/org/springframework/core/testfixture/io/buffer/DataBufferTestUtils.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2020 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.
diff --git a/spring-test/src/main/java/org/springframework/mock/http/client/reactive/MockClientHttpRequest.java b/spring-test/src/main/java/org/springframework/mock/http/client/reactive/MockClientHttpRequest.java
index 638a2446f17..c6568c1fca5 100644
--- a/spring-test/src/main/java/org/springframework/mock/http/client/reactive/MockClientHttpRequest.java
+++ b/spring-test/src/main/java/org/springframework/mock/http/client/reactive/MockClientHttpRequest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -149,18 +149,13 @@ public class MockClientHttpRequest extends AbstractClientHttpRequest {
 		Charset charset = Optional.ofNullable(getHeaders().getContentType()).map(MimeType::getCharset)
 				.orElse(StandardCharsets.UTF_8);
 
-		return getBody()
-				.reduce(bufferFactory().allocateBuffer(), (previous, current) -> {
-					previous.write(current);
-					DataBufferUtils.release(current);
-					return previous;
+		return DataBufferUtils.join(getBody())
+				.map(buffer -> {
+					String s = buffer.toString(charset);
+					DataBufferUtils.release(buffer);
+					return s;
 				})
-				.map(buffer -> bufferToString(buffer, charset));
-	}
-
-	private static String bufferToString(DataBuffer buffer, Charset charset) {
-		Assert.notNull(charset, "'charset' must not be null");
-		return buffer.toString(charset);
+				.defaultIfEmpty("");
 	}
 
 }
diff --git a/spring-test/src/main/java/org/springframework/mock/http/client/reactive/MockClientHttpResponse.java b/spring-test/src/main/java/org/springframework/mock/http/client/reactive/MockClientHttpResponse.java
index b553fc9ac7b..4e3d1a76adc 100644
--- a/spring-test/src/main/java/org/springframework/mock/http/client/reactive/MockClientHttpResponse.java
+++ b/spring-test/src/main/java/org/springframework/mock/http/client/reactive/MockClientHttpResponse.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -122,19 +122,13 @@ public class MockClientHttpResponse implements ClientHttpResponse {
 	 * charset of the Content-Type response or otherwise as "UTF-8".
 	 */
 	public Mono<String> getBodyAsString() {
-		Charset charset = getCharset();
-		return Flux.from(getBody())
-				.reduce(this.bufferFactory.allocateBuffer(), (previous, current) -> {
-					previous.write(current);
-					DataBufferUtils.release(current);
-					return previous;
+		return DataBufferUtils.join(getBody())
+				.map(buffer -> {
+					String s = buffer.toString(getCharset());
+					DataBufferUtils.release(buffer);
+					return s;
 				})
-				.map(buffer -> dumpString(buffer, charset));
-	}
-
-	private static String dumpString(DataBuffer buffer, Charset charset) {
-		Assert.notNull(charset, "'charset' must not be null");
-		return buffer.toString(charset);
+				.defaultIfEmpty("");
 	}
 
 	private Charset getCharset() {
diff --git a/spring-test/src/main/java/org/springframework/mock/http/server/reactive/MockServerHttpResponse.java b/spring-test/src/main/java/org/springframework/mock/http/server/reactive/MockServerHttpResponse.java
index 905ea67baf6..af068c8a903 100644
--- a/spring-test/src/main/java/org/springframework/mock/http/server/reactive/MockServerHttpResponse.java
+++ b/spring-test/src/main/java/org/springframework/mock/http/server/reactive/MockServerHttpResponse.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -142,20 +142,13 @@ public class MockServerHttpResponse extends AbstractServerHttpResponse {
 		Charset charset = Optional.ofNullable(getHeaders().getContentType()).map(MimeType::getCharset)
 				.orElse(StandardCharsets.UTF_8);
 
-		return getBody()
-				.reduce(bufferFactory().allocateBuffer(), (previous, current) -> {
-					previous.write(current);
-					DataBufferUtils.release(current);
-					return previous;
+		return DataBufferUtils.join(getBody())
+				.map(buffer -> {
+					String s = buffer.toString(charset);
+					DataBufferUtils.release(buffer);
+					return s;
 				})
-				.map(buffer -> bufferToString(buffer, charset));
-	}
-
-	private static String bufferToString(DataBuffer buffer, Charset charset) {
-		Assert.notNull(charset, "'charset' must not be null");
-		String str = buffer.toString(charset);
-		DataBufferUtils.release(buffer);
-		return str;
+				.defaultIfEmpty("");
 	}
 
 }
diff --git a/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/client/reactive/MockClientHttpRequest.java b/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/client/reactive/MockClientHttpRequest.java
index 321b48e7453..1fdd0edcd3b 100644
--- a/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/client/reactive/MockClientHttpRequest.java
+++ b/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/client/reactive/MockClientHttpRequest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -149,18 +149,13 @@ public class MockClientHttpRequest extends AbstractClientHttpRequest {
 		Charset charset = Optional.ofNullable(getHeaders().getContentType()).map(MimeType::getCharset)
 				.orElse(StandardCharsets.UTF_8);
 
-		return getBody()
-				.reduce(bufferFactory().allocateBuffer(), (previous, current) -> {
-					previous.write(current);
-					DataBufferUtils.release(current);
-					return previous;
+		return DataBufferUtils.join(getBody())
+				.map(buffer -> {
+					String s = buffer.toString(charset);
+					DataBufferUtils.release(buffer);
+					return s;
 				})
-				.map(buffer -> bufferToString(buffer, charset));
-	}
-
-	private static String bufferToString(DataBuffer buffer, Charset charset) {
-		Assert.notNull(charset, "'charset' must not be null");
-		return buffer.toString(charset);
+				.defaultIfEmpty("");
 	}
 
 }
diff --git a/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/client/reactive/MockClientHttpResponse.java b/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/client/reactive/MockClientHttpResponse.java
index 65815cf78f8..7ee7e6afb95 100644
--- a/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/client/reactive/MockClientHttpResponse.java
+++ b/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/client/reactive/MockClientHttpResponse.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -122,19 +122,13 @@ public class MockClientHttpResponse implements ClientHttpResponse {
 	 * charset of the Content-Type response or otherwise as "UTF-8".
 	 */
 	public Mono<String> getBodyAsString() {
-		Charset charset = getCharset();
-		return Flux.from(getBody())
-				.reduce(this.bufferFactory.allocateBuffer(), (previous, current) -> {
-					previous.write(current);
-					DataBufferUtils.release(current);
-					return previous;
+		return DataBufferUtils.join(getBody())
+				.map(buffer -> {
+					String s = buffer.toString(getCharset());
+					DataBufferUtils.release(buffer);
+					return s;
 				})
-				.map(buffer -> dumpString(buffer, charset));
-	}
-
-	private static String dumpString(DataBuffer buffer, Charset charset) {
-		Assert.notNull(charset, "'charset' must not be null");
-		return buffer.toString(charset);
+				.defaultIfEmpty("");
 	}
 
 	private Charset getCharset() {
diff --git a/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/MockServerHttpResponse.java b/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/MockServerHttpResponse.java
index 5a1f2b438a0..b3f95854e4e 100644
--- a/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/MockServerHttpResponse.java
+++ b/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/MockServerHttpResponse.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -142,20 +142,13 @@ public class MockServerHttpResponse extends AbstractServerHttpResponse {
 		Charset charset = Optional.ofNullable(getHeaders().getContentType()).map(MimeType::getCharset)
 				.orElse(StandardCharsets.UTF_8);
 
-		return getBody()
-				.reduce(bufferFactory().allocateBuffer(), (previous, current) -> {
-					previous.write(current);
-					DataBufferUtils.release(current);
-					return previous;
+		return DataBufferUtils.join(getBody())
+				.map(buffer -> {
+					String s = buffer.toString(charset);
+					DataBufferUtils.release(buffer);
+					return s;
 				})
-				.map(buffer -> bufferToString(buffer, charset));
-	}
-
-	private static String bufferToString(DataBuffer buffer, Charset charset) {
-		Assert.notNull(charset, "'charset' must not be null");
-		String s = buffer.toString(charset);
-		DataBufferUtils.release(buffer);
-		return s;
+				.defaultIfEmpty("");
 	}
 
 }