Polishing

spring-core/src/main/java/org/springframework/util/LinkedCaseInsensitiveMap.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -151,6 +151,7 @@ public class LinkedCaseInsensitiveMap<V> implements Map<String, V>, Serializable
 	}
 
 	@Override
+	@Nullable
 	public V getOrDefault(Object key, V defaultValue) {
 		if (key instanceof String) {
 			String caseInsensitiveKey = this.caseInsensitiveKeys.get(convertKey((String) key));
@@ -162,6 +163,7 @@ public class LinkedCaseInsensitiveMap<V> implements Map<String, V>, Serializable
 	}
 
 	@Override
+	@Nullable
 	public V put(String key, @Nullable V value) {
 		String oldKey = this.caseInsensitiveKeys.put(convertKey(key), key);
 		if (oldKey != null && !oldKey.equals(key)) {