TicketManager.java

class TicketManager {

    private int mNumberOfTickets = 100;

    void purchaseTickets(int amount) {

        someTimeIntensiveTask();

        if (mNumberOfTickets >= amount) {

            mNumberOfTickets = mNumberOfTickets - amount;

        } else {
            // Tickets all sold!
        }
    }

    private void someTimeIntensiveTask() {

        try {
            Thread.currentThread().sleep(1000);
            System.out.println(Thread.currentThread().getName() + " is making connection to database.........");
        } catch (Exception e) {

        }
    }
}