question: @ Override public int lastIndexOf ( Object o ) { if ( o == null ) { for ( int i = end - 1 ; i >= start ; i -- ) { if ( buffer [ i ] == null ) { return i - start ; } } } else { for ( int i = end - 1 ; i >= start ; i -- ) { if ( o . equals ( buffer [ i ] ) ) { return i - start ; } } } return - 1 ; }
target:  Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element.