diff --git a/spring-core/src/main/java/org/springframework/core/io/DefaultResourceLoader.java b/spring-core/src/main/java/org/springframework/core/io/DefaultResourceLoader.java
index 09fbbfd25b..27ed3bf1a0 100644
--- a/spring-core/src/main/java/org/springframework/core/io/DefaultResourceLoader.java
+++ b/spring-core/src/main/java/org/springframework/core/io/DefaultResourceLoader.java
@@ -79,7 +79,7 @@ public class DefaultResourceLoader implements ResourceLoader {
 	 * Specify the ClassLoader to load class path resources with, or {@code null}
 	 * for using the thread context class loader at the time of actual resource access.
 	 * <p>The default is that ClassLoader access will happen using the thread context
-	 * class loader at the time of this ResourceLoader's initialization.
+	 * class loader at the time of actual resource access (since 5.3).
 	 */
 	public void setClassLoader(@Nullable ClassLoader classLoader) {
 		this.classLoader = classLoader;
diff --git a/spring-web/src/main/java/org/springframework/http/HttpHeaders.java b/spring-web/src/main/java/org/springframework/http/HttpHeaders.java
index 9c07ada076..9c547634b2 100644
--- a/spring-web/src/main/java/org/springframework/http/HttpHeaders.java
+++ b/spring-web/src/main/java/org/springframework/http/HttpHeaders.java
@@ -1768,6 +1768,19 @@ public class HttpHeaders implements MultiValueMap<String, String>, Serializable
 	}
 
 
+	/**
+	 * Apply a read-only {@code HttpHeaders} wrapper around the given headers, if necessary.
+	 * <p>Also caches the parsed representations of the "Accept" and "Content-Type" headers.
+	 * @param headers the headers to expose
+	 * @return a read-only variant of the headers, or the original headers as-is
+	 * (in case it happens to be a read-only {@code HttpHeaders} instance already)
+	 * @since 5.3
+	 */
+	public static HttpHeaders readOnlyHttpHeaders(MultiValueMap<String, String> headers) {
+		return (headers instanceof HttpHeaders ?
+				readOnlyHttpHeaders((HttpHeaders) headers) : new ReadOnlyHttpHeaders(headers));
+	}
+
 	/**
 	 * Apply a read-only {@code HttpHeaders} wrapper around the given headers, if necessary.
 	 * <p>Also caches the parsed representations of the "Accept" and "Content-Type" headers.
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/function/client/DefaultWebClientBuilder.java b/spring-webflux/src/main/java/org/springframework/web/reactive/function/client/DefaultWebClientBuilder.java
index f7ba51ed10..0b87db5546 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/function/client/DefaultWebClientBuilder.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/function/client/DefaultWebClientBuilder.java
@@ -229,7 +229,7 @@ final class DefaultWebClientBuilder implements WebClient.Builder {
 	}
 
 	@Override
-	@SuppressWarnings("deprecation")
+	@Deprecated
 	public WebClient.Builder exchangeStrategies(Consumer<ExchangeStrategies.Builder> configurer) {
 		if (this.strategiesConfigurers == null) {
 			this.strategiesConfigurers = new ArrayList<>(4);
@@ -266,7 +266,7 @@ final class DefaultWebClientBuilder implements WebClient.Builder {
 				.orElse(exchange) : exchange);
 		return new DefaultWebClient(filteredExchange, initUriBuilderFactory(),
 				this.defaultHeaders != null ? HttpHeaders.readOnlyHttpHeaders(this.defaultHeaders) : null,
-				this.defaultCookies != null ? HttpHeaders.readOnlyHttpHeaders(this.defaultCookies) : null,
+				this.defaultCookies != null ? CollectionUtils.unmodifiableMultiValueMap(this.defaultCookies) : null,
 				this.defaultRequest, new DefaultWebClientBuilder(this));
 	}
 
@@ -290,10 +290,8 @@ final class DefaultWebClientBuilder implements WebClient.Builder {
 		if (CollectionUtils.isEmpty(this.strategiesConfigurers)) {
 			return this.strategies != null ? this.strategies : ExchangeStrategies.withDefaults();
 		}
-
 		ExchangeStrategies.Builder builder =
 				this.strategies != null ? this.strategies.mutate() : ExchangeStrategies.builder();
-
 		this.strategiesConfigurers.forEach(configurer -> configurer.accept(builder));
 		return builder.build();
 	}
@@ -308,8 +306,4 @@ final class DefaultWebClientBuilder implements WebClient.Builder {
 		return factory;
 	}
 
-	private static <K, V> MultiValueMap<K, V> unmodifiableCopy(MultiValueMap<K, V> map) {
-		return CollectionUtils.unmodifiableMultiValueMap(new LinkedMultiValueMap<>(map));
-	}
-
 }