如何在Java中使用正则表达式查找重复的字符？

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
    public static void main(String[] args) {
        String input = "helloooworldd";
        String regex = "(\\w)\\1+";

        Pattern pattern = Pattern.compile(regex);
        Matcher matcher = pattern.matcher(input);

        while (matcher.find()) {
            System.out.println("重复的字符: " + matcher.group(1));
        }
    }
}

重复的字符: l
重复的字符: o
重复的字符: d