diff --git a/spring-core/src/main/java/org/springframework/util/MimeTypeUtils.java b/spring-core/src/main/java/org/springframework/util/MimeTypeUtils.java
index 08fad1c431..4a88a27081 100644
--- a/spring-core/src/main/java/org/springframework/util/MimeTypeUtils.java
+++ b/spring-core/src/main/java/org/springframework/util/MimeTypeUtils.java
@@ -167,6 +167,7 @@ public abstract class MimeTypeUtils {
 	private static volatile Random random;
 
 	static {
+		// Not using "parseMimeType" to avoid static init cost
 		ALL = new MimeType("*", "*");
 		APPLICATION_JSON = new MimeType("application", "json");
 		APPLICATION_OCTET_STREAM = new MimeType("application", "octet-stream");
diff --git a/spring-web/src/main/java/org/springframework/http/MediaType.java b/spring-web/src/main/java/org/springframework/http/MediaType.java
index 78db60611b..0875862b49 100644
--- a/spring-web/src/main/java/org/springframework/http/MediaType.java
+++ b/spring-web/src/main/java/org/springframework/http/MediaType.java
@@ -323,6 +323,7 @@ public class MediaType extends MimeType implements Serializable {
 
 
 	static {
+		// Not using "valueOf' to avoid static init cost
 		ALL = new MediaType("*", "*");
 		APPLICATION_ATOM_XML = new MediaType("application", "atom+xml");
 		APPLICATION_FORM_URLENCODED = new MediaType("application", "x-www-form-urlencoded");
@@ -552,6 +553,7 @@ public class MediaType extends MimeType implements Serializable {
 		if (!StringUtils.hasLength(mediaTypes)) {
 			return Collections.emptyList();
 		}
+		// Avoid using java.util.stream.Stream in hot paths
 		List<String> tokenizedTypes = MimeTypeUtils.tokenize(mediaTypes);
 		List<MediaType> result = new ArrayList<>(tokenizedTypes.size());
 		for (String type : tokenizedTypes) {