Polish contribution

See gh-25446

spring-orm/src/main/java/org/springframework/orm/hibernate5/SessionHolder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -49,6 +49,7 @@ public class SessionHolder extends EntityManagerHolder {
 	private FlushMode previousFlushMode;
 
 
+	@SuppressWarnings("cast")
 	public SessionHolder(Session session) {
 		// Check below is always true against Hibernate >= 5.2 but not against 5.0/5.1 at runtime
 		super(session instanceof EntityManager ? session : null);