как всегда всё правильно, только пишет условие не выполняется).

package com.javarush.task.pro.task09.task0908; /* Двоично-шестнадцатеричный конвертер */ public class Solution { private static String[] symbols = {"2", "3", "4", "5", "6", "7", "8", "9"}; public static void main(String[] args) { // String binaryNumber = "103"; String binaryNumber = "100111010000"; System.out.println("Двоичное число " + binaryNumber + " равно шестнадцатеричному числу " + toHex(binaryNumber)); String hexNumber = "9d0"; System.out.println("Шестнадцатеричное число " + hexNumber + " равно двоичному числу " + toBinary(hexNumber)); } public static boolean isBinaryCorrect(String binaryNumber){ for(int i = 0; i <symbols.length; i++) { if (binaryNumber.contains(symbols[i])) return false; } return true; } public static String toHex(String binaryNumber) { String hexNumber=""; if (binaryNumber!=null && !binaryNumber.equals("")) { if (isBinaryCorrect(binaryNumber)) { // if (binaryNumber.contains("0") && binaryNumber.contains("1")) { if (binaryNumber.length()%4!=0) { if (binaryNumber.length()%4==1) {binaryNumber="000"+binaryNumber;} else if (binaryNumber.length()%4==2) {binaryNumber="00"+binaryNumber;} else if (binaryNumber.length()%4==3) binaryNumber="0"+binaryNumber; } char[] chars=binaryNumber.toCharArray(); for (int i=0; i <binaryNumber.length(); i=i+4) { String str=""; for (int j=i; j <i+4; j++) { str=str+chars[j]; } switch (str){ case ("0000"): hexNumber=hexNumber+"0"; break; case ("0001"): hexNumber=hexNumber+"1"; break; case ("0010"): hexNumber=hexNumber+"2"; break; case ("0011"): hexNumber=hexNumber+"3"; break; case ("0100"): hexNumber=hexNumber+"4"; break; case ("0101"): hexNumber=hexNumber+"5"; break; case ("0110"): hexNumber=hexNumber+"6"; break; case ("0111"): hexNumber=hexNumber+"7"; break; case ("1000"): hexNumber=hexNumber+"8"; break; case ("1001"): hexNumber=hexNumber+"9"; break; case ("1010"): hexNumber=hexNumber+"a"; break; case ("1011"): hexNumber=hexNumber+"b"; break; case ("1100"): hexNumber=hexNumber+"c"; break; case ("1101"): hexNumber=hexNumber+"d"; break; case ("1110"): hexNumber=hexNumber+"e"; break; case ("1111"): hexNumber=hexNumber+"f"; break; default: hexNumber=hexNumber+""; break; } }; } else return hexNumber; } return hexNumber; } public static String toBinary(String hexNumber) { String binaryNumber=""; if (hexNumber!=null && !hexNumber.equals("")){ if (hexNumber.contains("0") ||hexNumber.contains("1") ||hexNumber.contains("2") ||hexNumber.contains("3") ||hexNumber.contains("4") ||hexNumber.contains("5") ||hexNumber.contains("6") ||hexNumber.contains("7") ||hexNumber.contains("8") ||hexNumber.contains("9") ||hexNumber.contains("a") ||hexNumber.contains("b") ||hexNumber.contains("c") ||hexNumber.contains("d") ||hexNumber.contains("e") ||hexNumber.contains("f")){ char[] chars=hexNumber.toCharArray(); for (int i = 0; i <hexNumber.length(); i++) { switch (chars[i]){ case ('0'): binaryNumber=binaryNumber+"0000"; break; case ('1'): binaryNumber=binaryNumber+"0001"; break; case ('2'): binaryNumber=binaryNumber+"0010"; break; case ('3'): binaryNumber=binaryNumber+"0011"; break; case ('4'): binaryNumber=binaryNumber+"0100"; break; case ('5'): binaryNumber=binaryNumber+"0101"; break; case ('6'): binaryNumber=binaryNumber+"0110"; break; case ('7'): binaryNumber=binaryNumber+"0111"; break; case ('8'): binaryNumber=binaryNumber+"1000"; break; case ('9'): binaryNumber=binaryNumber+"1001"; break; case ('a'): binaryNumber=binaryNumber+"1010"; break; case ('b'): binaryNumber=binaryNumber+"1011"; break; case ('c'): binaryNumber=binaryNumber+"1100"; break; case ('d'): binaryNumber=binaryNumber+"1101"; break; case ('e'): binaryNumber=binaryNumber+"1110"; break; case ('f'): binaryNumber=binaryNumber+"1111"; break; default: binaryNumber=binaryNumber+""; break; } } } } return binaryNumber; } }