question: private Integer insertAllContacts ( Iterator < String > contactsIter ) { final ArrayList < ContentProviderOperation > batchOperation = new ArrayList < ContentProviderOperation > ( ) ; while ( contactsIter . hasNext ( ) ) addContact ( contactsIter . next ( ) , batchOperation ) ; try { ContentProviderResult [ ] results = mContentResolver . applyBatch ( ContactsContract . AUTHORITY , batchOperation ) ; return results . length / 2 ; } catch ( RemoteException e ) { e . printStackTrace ( ) ; } catch ( OperationApplicationException e ) { e . printStackTrace ( ) ; } return 0 ; }
target:  Synchronously insert all contacts designated by the Iterator.