Что не нравтися валидатору?
public class Solution {
    public static void main(String[] args) {
        // напишите тут ваш код
        StringBuilder string = new StringBuilder();
        ArrayList<Integer> numbers = new ArrayList<>();

        try (BufferedReader reader = new BufferedReader(new InputStreamReader(System.in))) {
            String fileName = reader.readLine();
            try (FileInputStream fileInputStream = new FileInputStream(fileName)) {
                int data;

                while ((data = fileInputStream.read()) != -1) {

                    if (((char) data) != '\n' && ((char) data) != '\r')
                        string.append((char) data);
                    else {
                        try {
                            int num = Integer.parseInt(string.toString());
                            if (num % 2 == 0) {
                                numbers.add(num);
                            }
                        } catch (NumberFormatException ignored) {

                        }
                        string = new StringBuilder();
                    }
                }

            } catch (IOException e) {

            }
        } catch (IOException e) {

        }

        Collections.sort(numbers);

        numbers.forEach(System.out::println);
    }
}