diff --git a/spring-core/src/main/java/org/springframework/util/CompositeMap.java b/spring-core/src/main/java/org/springframework/util/CompositeMap.java
index 37e9f25034b2..5af883f269e9 100644
--- a/spring-core/src/main/java/org/springframework/util/CompositeMap.java
+++ b/spring-core/src/main/java/org/springframework/util/CompositeMap.java
@@ -117,7 +117,7 @@ public V put(K key, V value) {
 	}
 
 	@Override
-	public V remove(Object key) {
+	public @Nullable V remove(Object key) {
 		V firstResult = this.first.remove(key);
 		V secondResult = this.second.remove(key);
 		if (firstResult != null) {
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaders.java b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaders.java
index 4691f842be25..d55e0f30ef5a 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaders.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompHeaders.java
@@ -510,7 +510,7 @@ public List<String> put(String key, List<String> value) {
 	}
 
 	@Override
-	public List<String> remove(Object key) {
+	public @Nullable List<String> remove(Object key) {
 		return this.headers.remove(key);
 	}