Fix checkstyle errors

(cherry picked from commit bd98343b9c)

servlet/java-configuration/saml2/login/src/main/java/example/IndexController.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2021 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package example;
 
 import org.springframework.security.core.annotation.AuthenticationPrincipal;