question: public static String addAsterisk ( String s , int index ) { if ( s != null ) { index = Math . min ( index , s . length ( ) ) ; s = s . substring ( 0 , index ) + "[*]" + s . substring ( index ) ; } return s ; }
target:  Add an asterisk ('[*]') at the given position. This format is used to show where parsing failed in a statement.