• Both threads check → seat available → both book successfully.
• Result: Multiple tickets can be issued for 1 seat → this is called data inconsistency (double booking).
• This happens because:
  • The seat availability check and booking update are not atomic (not done one at a time).
  • Multiple threads are allowed to enter the critical section simultaneously.

class BookMovieSeat
{
    int total_seats=10;

    void bookSeat(int seats, String name)
    {
        if(total_seats>=seats)
        {
            System.out.println(name+" booked "+seats+" seats successfully");
            total_seats=total_seats-seats;
            System.out.println("Total seats left : "+total_seats);
        }
        else
        {
            System.err.println(name+" sorry...!! seats not left");
            System.err.println("Total seats left : "+total_seats);
        }
    }
}
class MyThread extends Thread
{
    BookMovieSeat bts;
    int seats;

    public MyThread(BookMovieSeat bts, int seats)
    {
        this.bts=bts;
        this.seats=seats;
    }

    public void run()
    {
        bts.bookSeat(seats, Thread.currentThread().getName());
    }
}
public class MovieBookingApp
{
    public static void main(String[] args)
    {
        BookMovieSeat bts=new BookMovieSeat();

        MyThread deepak=new MyThread(bts, 6);
        deepak.setName("Deepak");
        deepak.start();

        MyThread amit=new MyThread(bts, 5);
        amit.setName("Amit");
        amit.start();
    }
}

Deepak booked 6 seats successfully
Total seats left : 4
Amit booked 5 seats successfully
Total seats left : -1