Java prints out the digits based on the number of positive integers in reverse order

Give me a positive integer with no more than 5 digits. Find out how many digits it is.

Program design:

import java.util.Scanner;
public class Ex24 {
public static void main(String[] args) {
  Ex24 tn = new Ex24();
  Scanner s = new Scanner(System.in);
  long a = s.nextLong();
  if(a < 0 || a > 100000) {
  System.out.println("Error Input, please run this program Again");
  System.exit(0);
  }
  if(a >=0 && a <=9) {
  System.out.println( a + " is 1 digits ");
  System.out.println(" The output in reverse order is " + '\n' + a);
  } else if(a >= 10 && a <= 99) {
  System.out.println(a + " is 2 digits ");
  System.out.println(" The output in reverse order is " );
  tn.converse(a);
  } else if(a >= 100 && a <= 999) {
  System.out.println(a + " is 3 digits ");
  System.out.println(" The output in reverse order is " );
  tn.converse(a);
  } else if(a >= 1000 && a <= 9999) {
  System.out.println(a + " is 4 digits ");
  System.out.println(" The output in reverse order is " );
  tn.converse(a);
  } else if(a >= 10000 && a <= 99999) {
  System.out.println(a + " is 5 digits ");
  System.out.println(" The output in reverse order is " );
  tn.converse(a);
  }
}
public void converse(long l) {
  String s = Long.toString(l);
  char[] ch = s.toCharArray();
  for(int i=ch.length-1; i>=0; i--) {
  System.out.print(ch[i]);
  }
}
}