Implemented the Item Mapper functionality

dspace-api/src/main/java/org/dspace/content/CollectionServiceImpl.java

@@ -636,6 +636,7 @@ public class CollectionServiceImpl extends DSpaceObjectServiceImpl<Collection> i
             //Remove the item from the collection if we have multiple collections
             item.removeCollection(collection);
 
+
         }
 
         context.addEvent(new Event(Event.REMOVE, Constants.COLLECTION,