DATAMONGO-2044 make ensureNotIterable actually check if object is iterable

Author: GotoFinal

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/MongoTemplate.java

@@ -151,23 +151,13 @@
  * @author Borislav Rangelov
  * @author duozhilin
  * @author Andreas Zink
+ * @author Bartłomiej Mazur
  */
 @SuppressWarnings("deprecation")
 public class MongoTemplate implements MongoOperations, ApplicationContextAware, IndexOperationsProvider {
 
 	private static final Logger LOGGER = LoggerFactory.getLogger(MongoTemplate.class);
 	private static final WriteResultChecking DEFAULT_WRITE_RESULT_CHECKING = WriteResultChecking.NONE;
-	private static final Collection<String> ITERABLE_CLASSES;
-
-	static {
-
-		Set<String> iterableClasses = new HashSet<>();
-		iterableClasses.add(List.class.getName());
-		iterableClasses.add(Collection.class.getName());
-		iterableClasses.add(Iterator.class.getName());
-
-		ITERABLE_CLASSES = Collections.unmodifiableCollection(iterableClasses);
-	}
 
 	private final MongoConverter mongoConverter;
 	private final MappingContext<? extends MongoPersistentEntity<?>, MongoPersistentProperty> mappingContext;
@@ -1150,7 +1140,7 @@ public <T> T insert(T objectToSave, String collectionName) {
 
 	protected void ensureNotIterable(@Nullable Object o) {
 		if (null != o) {
-			if (o.getClass().isArray() || ITERABLE_CLASSES.contains(o.getClass().getName())) {
+			if (o.getClass().isArray() || (o instanceof Iterable) || (o instanceof Iterator)) {
 				throw new IllegalArgumentException("Cannot use a collection here.");
 			}
 		}