question: @ SuppressWarnings ( "unchecked" ) private void expungeStaleEntries ( ) { synchronized ( sync ) { ListWeakReference r ; while ( ( r = ( ListWeakReference ) queue . poll ( ) ) != null ) { ListEntry le = r . getListEntry ( ) ; int i = list . indexOf ( le ) ; if ( i != - 1 ) { list . remove ( i ) ; } } } }
target:  Expunge stale entries from the list.