question: private static int compare ( int fromIndex , CharSequence left , CharSequence right ) { if ( left == null ) return - 1 ; if ( right == null ) return 1 ; for ( int i = fromIndex , n = MathLib . min ( left . length ( ) , right . length ( ) ) ; i < n ; i ++ ) { char c1 = left . charAt ( i ) ; char c2 = right . charAt ( i ) ; if ( c1 != c2 ) return c1 - c2 ; } return left . length ( ) - right . length ( ) ; }
target:  Compares the two characters sequences starting at the specified index 