diff --git a/spring-context/src/main/java/org/springframework/context/support/StaticMessageSource.java b/spring-context/src/main/java/org/springframework/context/support/StaticMessageSource.java
index 26df79d7b71183f2b3af820ad1c5f25929e307c8..5f2596b4cf0985399370c9d16b5141e6f053e0fa 100644
--- a/spring-context/src/main/java/org/springframework/context/support/StaticMessageSource.java
+++ b/spring-context/src/main/java/org/springframework/context/support/StaticMessageSource.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -43,6 +43,7 @@ public class StaticMessageSource extends AbstractMessageSource {
 
 
 	@Override
+	@Nullable
 	protected String resolveCodeWithoutArguments(String code, Locale locale) {
 		return this.messages.get(code + '_' + locale.toString());
 	}
diff --git a/spring-context/src/test/java/org/springframework/context/support/StaticMessageSourceTests.java b/spring-context/src/test/java/org/springframework/context/support/StaticMessageSourceTests.java
index b5bb82ebe7e81c86ceef31fcfb7494a000209dae..68d0dcf317c2025c45e45d6d606a9e780a074c24 100644
--- a/spring-context/src/test/java/org/springframework/context/support/StaticMessageSourceTests.java
+++ b/spring-context/src/test/java/org/springframework/context/support/StaticMessageSourceTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -62,7 +62,6 @@ public class StaticMessageSourceTests extends AbstractApplicationContextTests {
 	@Test
 	@Override
 	public void count() {
-		// These are only checked for current Ctx (not parent ctx)
 		assertCount(15);
 	}