Не пропускает валидатор.

package com.javarush.task.task19.task1914; /* Решаем пример */ import java.io.ByteArrayOutputStream; import java.io.PrintStream; import java.util.ArrayList; public class Solution { public static TestString testString = new TestString(); public static void main(String[] args) { PrintStream out = System.out; ByteArrayOutputStream tempStorage = new ByteArrayOutputStream(); PrintStream newout = new PrintStream(tempStorage); System.setOut(newout); testString.printSomething(); System.setOut(out); System.out.println(testString.calculator(tempStorage)); } public static class TestString { public void printSomething() { System.out.println("3 + 6 = "); } public int calculator(ByteArrayOutputStream tempStorage) { ArrayList<Integer> intArr = new ArrayList<>(); byte[] byteArr = tempStorage.toByteArray(); char sign = ' '; String buffer = ""; for(int i = 0; i < byteArr.length; i++){ buffer = ""; if(Character.isDigit(byteArr[i])) { while (Character.isDigit(byteArr[i])) { buffer += (char) byteArr[i]; i++; } intArr.add(Integer.parseInt(buffer)); } if(byteArr[i] == '+' || byteArr[i] == '-' || byteArr[i] == '*') sign = (char)byteArr[i]; } int result = 0; if(sign == '+') result = intArr.get(0) + intArr.get(1); else if(sign == '-') result = intArr.get(0) - intArr.get(1); else if(sign == '*') result = intArr.get(0) * intArr.get(1); return result; } } }