Minor refactoring

- Remove unused clone() code left-over from previous way of cloning.
- Lazy instantiation of ServerCodecConfigurer in
  HttpWebHandlerAdapter since in most cases the configurer instance
  is set externally.

Closes gh-26263

spring-web/src/main/java/org/springframework/http/codec/support/BaseDefaultCodecs.java

@@ -217,12 +217,6 @@ class BaseDefaultCodecs implements CodecConfigurer.DefaultCodecs, CodecConfigure
 		initObjectWriters();
 	}
 
-	@Override
-	public void protobufDecoder(Decoder<?> decoder) {
-		this.protobufDecoder = decoder;
-		initTypedReaders();
-	}
-
 	@Override
 	public void jackson2SmileDecoder(Decoder<?> decoder) {
 		this.jackson2SmileDecoder = decoder;
@@ -235,6 +229,12 @@ class BaseDefaultCodecs implements CodecConfigurer.DefaultCodecs, CodecConfigure
 		initObjectWriters();
 	}
 
+	@Override
+	public void protobufDecoder(Decoder<?> decoder) {
+		this.protobufDecoder = decoder;
+		initTypedReaders();
+	}
+
 	@Override
 	public void protobufEncoder(Encoder<?> encoder) {
 		this.protobufEncoder = encoder;

spring-web/src/main/java/org/springframework/http/codec/support/ClientDefaultCodecsImpl.java

@@ -86,15 +86,6 @@ class ClientDefaultCodecsImpl extends BaseDefaultCodecs implements ClientCodecCo
 		initObjectReaders();
 	}
 
-	@Override
-	public ClientDefaultCodecsImpl clone() {
-		ClientDefaultCodecsImpl codecs = new ClientDefaultCodecsImpl();
-		codecs.multipartCodecs = this.multipartCodecs;
-		codecs.sseDecoder = this.sseDecoder;
-		codecs.partWritersSupplier = this.partWritersSupplier;
-		return codecs;
-	}
-
 	@Override
 	protected void extendObjectReaders(List<HttpMessageReader<?>> objectReaders) {
 

spring-web/src/main/java/org/springframework/web/server/adapter/HttpWebHandlerAdapter.java

@@ -81,7 +81,8 @@ public class HttpWebHandlerAdapter extends WebHandlerDecorator implements HttpHa
 
 	private WebSessionManager sessionManager = new DefaultWebSessionManager();
 
-	private ServerCodecConfigurer codecConfigurer = ServerCodecConfigurer.create();
+	@Nullable
+	private ServerCodecConfigurer codecConfigurer;
 
 	private LocaleContextResolver localeContextResolver = new AcceptHeaderLocaleContextResolver();
 
@@ -143,6 +144,9 @@ public class HttpWebHandlerAdapter extends WebHandlerDecorator implements HttpHa
 	 * Return the configured {@link ServerCodecConfigurer}.
 	 */
 	public ServerCodecConfigurer getCodecConfigurer() {
+		if (this.codecConfigurer == null) {
+			setCodecConfigurer(ServerCodecConfigurer.create());
+		}
 		return this.codecConfigurer;
 	}