I'm trying to list the elements in the condition, how?

Question

Java

Hello, I'm just learning Java. And now I ran into a problem, the program reads a number in the hexadecimal number system from the keyboard, and if the user "accidentally" enters a letter that is not part of the hexadecimal number system, write to him that he made a mistake. So far my code is this:

import java.util.*;
public class 987 {
  static Scanner sc = new Scanner(System.in);

  public static void main(String[] args) {
    System.out.print("Введи гексо число: ");
    String cislo = sc.next();
    cislo = cislo.toUpperCase();
    
    
    
    char[] kontrola = cislo.toCharArray();
    
    for(int i = 0; i<kontrola.length; i++){
            
      if(kontrola[i] == 'G'){  
                    
        kontrola[i] = '.';
      
            }	
    }
  }

}

And in that part with the condition, I wanted to list all the other letters from the alphabet that do not fit, but it doesn’t work like that, how can it be written differently?
Thanks in advance

Answer 1

Integer res = 0;
try {
    res = Integer. parseInt(aString, 16);
} catch(NumberFormatException ex) {
    System.out.println("кисо, куку!")
}