Avoid use of Optional wrapper to get List<MediaType>

See gh-26170

spring-web/src/main/java/org/springframework/http/MediaTypeFactory.java

 /*
- * 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.
@@ -112,10 +112,12 @@ public final class MediaTypeFactory {
 	 * @return the corresponding media types, or an empty list if none found
 	 */
 	public static List<MediaType> getMediaTypes(@Nullable String filename) {
-		return Optional.ofNullable(StringUtils.getFilenameExtension(filename))
-				.map(s -> s.toLowerCase(Locale.ENGLISH))
-				.map(fileExtensionToMediaTypes::get)
-				.orElse(Collections.emptyList());
+		List<MediaType> mediaTypes = null;
+		String ext = StringUtils.getFilenameExtension(filename);
+		if (ext != null) {
+			mediaTypes = fileExtensionToMediaTypes.get(ext.toLowerCase(Locale.ENGLISH));
+		}
+		return (mediaTypes != null ? mediaTypes : Collections.emptyList());
 	}
 
 }

spring-webmvc/src/main/java/org/springframework/web/servlet/resource/ResourceHttpRequestHandler.java

@@ -736,7 +736,10 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 				mediaType = this.mediaTypes.get(ext.toLowerCase(Locale.ENGLISH));
 			}
 			if (mediaType == null) {
-				mediaType = MediaTypeFactory.getMediaType(filename).orElse(null);
+				List<MediaType> mediaTypes = MediaTypeFactory.getMediaTypes(filename);
+				if (!CollectionUtils.isEmpty(mediaTypes)) {
+					mediaType = mediaTypes.get(0);
+				}
 			}
 			if (mediaType != null) {
 				result = mediaType;