Worm Ipsum 50

package exams.retakeApril;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Collections;
import java.util.Map;
import java.util.TreeMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class P02_WormIpsum {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        String input = "";
        //String regex = "^([A-Z][^.]*)([.])$";
        String regex = "^([A-Z][^.]*)([.])$";

        Pattern pattern = Pattern.compile(regex);

        while (true) {
            input = reader.readLine();
            if ("Worm Ipsum".equals(input)) break;

            Matcher matcher = pattern.matcher(input);

            if (matcher.find()) {

                char repeatLetter = 0;
                String[] tokens = input.split("\\s+");
                for (int i = 0; i < tokens.length; i++) {
                    if (tokens[i].endsWith(".")) {
                        tokens[i] = tokens[i].replaceAll("\\.", "");
                    }
                    Map<Character, Integer> map = new TreeMap<>();
                    for (int j = 0; j < tokens[i].length(); j++) {
                        char letter = tokens[i].charAt(j);
                        if (!map.containsKey(letter)) {
                            map.put(letter, 1);
                        } else {
                            map.put(letter, map.get(letter) + 1);
                        }
                    }

                    int maxValueInMap = Collections.max(map.values());
                    for (Map.Entry<Character, Integer> entry : map.entrySet()) {
                        if (maxValueInMap > 1) {
                            if (entry.getValue() == maxValueInMap) {
                                repeatLetter = entry.getKey();
                                tokens[i] = repeatString(repeatLetter, tokens[i].length());
                            }
                        }
                    }
                }
                System.out.printf("%s.%n", String.join(" ", tokens));
            }
        }
    }
    public static String repeatString(char letter, int counter) {
        String result = "";
        for (int i = 0; i < counter; i++) {
            result += letter;
        }
        return result;
    }
}