请教一个关于java正则表达式的问题

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

class Test {
    public static void main(String[] args) throws PatternSyntaxException {
        String subjectString = "fdjfk23jkj0 ,. djfk !s2SJDKd djfk 232 : ! d .. s";
        List<String> matchList = new ArrayList<String>();
        Pattern regex = Pattern.compile("\\p{Alnum}+", Pattern.MULTILINE);
        Matcher regexMatcher = regex.matcher(subjectString);
        while (regexMatcher.find()) {
            matchList.add(regexMatcher.group(0));
        }
        System.out.println(matchList);
    }
}