Understanding try & catch and error handling

Question

import java.util.Scanner;

public class Lab4_5 {
    public static void main(String[]args) {
        Scanner scan= new Scanner(System.in);

        int rows=0;
              


        

Answer 1

String choice2=scan.next();
if(choice2.equals(y)){
  System.out.println("How many rows/columns(5-21)?");
try
{
rows=scan.nextInt();
}catch(Exception e)
{
rows = -1;
}
 while(rows<5||rows>21){
  System.out.println("That is either out of range or not an integer, try again! ");
try
{
rows=scan.nextInt();
}catch(Exception e)
{
rows = -1;
}
}