question: public static List < CoreLabel > toCharacterSequence ( Sequence < IString > tokenSequence ) { List < CoreLabel > charSequence = new ArrayList < > ( tokenSequence . size ( ) * 7 ) ; for ( IString token : tokenSequence ) { String tokenStr = token . toString ( ) ; if ( charSequence . size ( ) > 0 ) { CoreLabel charLabel = new CoreLabel ( ) ; charLabel . set ( CoreAnnotations . TextAnnotation . class , WHITESPACE ) ; charLabel . set ( CoreAnnotations . CharAnnotation . class , WHITESPACE ) ; charLabel . set ( CoreAnnotations . ParentAnnotation . class , WHITESPACE ) ; charLabel . set ( CoreAnnotations . CharacterOffsetBeginAnnotation . class , - 1 ) ; charLabel . setIndex ( charSequence . size ( ) ) ; charSequence . add ( charLabel ) ; } for ( int j = 0 , size = tokenStr . length ( ) ; j < size ; ++ j ) { CoreLabel charLabel = new CoreLabel ( ) ; String ch = String . valueOf ( tokenStr . charAt ( j ) ) ; charLabel . set ( CoreAnnotations . TextAnnotation . class , ch ) ; charLabel . set ( CoreAnnotations . CharAnnotation . class , ch ) ; charLabel . set ( CoreAnnotations . ParentAnnotation . class , tokenStr ) ; charLabel . set ( CoreAnnotations . CharacterOffsetBeginAnnotation . class , j ) ; charLabel . setIndex ( charSequence . size ( ) ) ; charSequence . add ( charLabel ) ; } } return charSequence ; }
target:  Convert a tokenized sequence to a character string.