В чем ошибка?
package com.javarush.task.task07.task0727;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
/*
Меняем функциональность
*/
public class Solution {
public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
ArrayList<String> strings = new ArrayList<String>();
while (true) {
String string = reader.readLine();
if (string == null || string.isEmpty()) break;
strings.add(string);
}
ArrayList<String> resultStrings = new ArrayList<String>();
for (int i = 0; i < strings.size(); i++) {
String string = strings.get(i);
resultStrings.add(string.toUpperCase());
}
for (int i = 0; i < resultStrings.size(); i++) {
System.out.println(resultStrings.get(i));
}
}
}