add an example to jdoc of SS.fetch()

Signed-off-by: Gavin King <gavin@hibernate.org>

Author: gavinking

hibernate-core/src/main/java/org/hibernate/StatelessSession.java

@@ -267,9 +267,15 @@ public interface StatelessSession extends SharedSessionContract {
 
 /**
  * Fetch an association or collection that's configured for lazy loading.
+ * <pre>
+ * Book book = session.get(Book.class, isbn); // book is immediately detached
+ * session.fetch(book.getAuthors()); // fetch the associated authors
+ * book.getAuthors().forEach(author -> ... ); // iterate the collection
+ * </pre>
  * <p>
  * Warning: this operation in a stateless session is quite sensitive
- * to data aliasing effects and should be used with great care.
+ * to data aliasing effects and should be used with great care. It's
+ * usually better to fetch associations using eager join fetching.
  *
  * @param association a lazy-loaded association
  *