diff --git a/spring-core/src/main/java/org/springframework/util/LinkedCaseInsensitiveMap.java b/spring-core/src/main/java/org/springframework/util/LinkedCaseInsensitiveMap.java
index 5cdd9f12438..1b70fa55509 100644
--- a/spring-core/src/main/java/org/springframework/util/LinkedCaseInsensitiveMap.java
+++ b/spring-core/src/main/java/org/springframework/util/LinkedCaseInsensitiveMap.java
@@ -273,7 +273,7 @@ public class LinkedCaseInsensitiveMap<V> implements Map<String, V>, Serializable
 	}
 
 	@Override
-	public boolean equals(Object obj) {
+	public boolean equals(@Nullable Object obj) {
 		return this.targetMap.equals(obj);
 	}