How can I fix this java?

Few points to note:-

1. You don't need System.exit()
2. In java variables are only accessible inside their scope i.e. the region they are created in.

I tried to rewrite code as following:-

import java.util.Scanner;

public class Bus {
    int busCount =0;
    int passengerCount =0;
    Scanner scanner= new Scanner(System.in);

    public static void main(String args[]){
        Bus bus = new Bus();
        bus.getResults();
    }

    private void addBusAndPassenger(String input){
        try{
            int a = Integer.parseInt(input);
            busCount = busCount + 1;
            passengerCount = passengerCount + a;
        }catch(NumberFormatException e){
            System.out.println("Please provide integer or X as input");
        }
    }

    private void getResults(){
        String a =null;
        while (!("X".equals(a))){
            System.out.print("How many passengers were on the bus? ");
            a = scanner.nextLine();
            if("X".equals(a))
                break;

            addBusAndPassenger(a);
        }
        System.out.println("There were a total of " + passengerCount + " passengers on " + busCount + " buses.");
    }
}