Java End Term: 13 April 2025, Set QDD3 (January 2025 term)

1class Shared {
2    static int count = 2000;
3}
4class Subtractor extends Thread {
5    public void run() {
6        for (int i = 0; i < 1000; i++) {
7            Shared.count--;
8        }
9    }
10}
11public class Test {
12    public static void main(String[] args) throws InterruptedException {
13        Thread t1 = new Subtractor();
14        Thread t2 = new Subtractor();
15        t1.start();
16        t2.start();
17        t1.join();
18        t2.join();
19        System.out.print(Shared.count);
20    }
21}

1class PaymentException extends Exception {
2    public PaymentException(String message) {
3        super(message);
4    }
5}
6class OrderProcessingException extends Exception {
7    public OrderProcessingException(String message) {
8        super(message);
9    }
10}
11class OrderService {
12    public void placeOrder() throws OrderProcessingException {
13        try {
14            // if(payment fails)
15            throw new PaymentException("Payment not done");
16            // else process the order
17        } catch (PaymentException e) {
18            OrderProcessingException oe = new OrderProcessingException
19                                          ("Order Failed");
20            oe.initCause(e);
21            throw oe;
22        }
23    }
24}
25public class Test {
26    public static void main(String[] args) {
27        OrderService orderService = new OrderService();
28        try {
29            orderService.placeOrder();
30        } catch (OrderProcessingException e) {
31            System.out.println(e.getMessage());
32            System.out.println("Root cause: " + e.getCause().getMessage());
33        }
34    }
35}

1package creatures;
2class Animal {
3    private String name;
4    private String habitat;
5    private int legs;
6    // Constructor to initialize instance variables
7    public String getName(String name) {
8        return name;
9    }
10    private String getHabitat(String habitat) {
11        return habitat;
12    }
13    protected int getLegs(int legs) {
14        return legs;
15    }
16    public int showLegs(int legs) {
17        return getLegs(legs);
18    }
19}
20class Bird extends Animal {
21    public void info() {
22        System.out.println("This is a Bird.");
23    }
24    public void displayHabitat() {
25        System.out.println("Bird's habitat: " + getHabitat("Trees"));
26    }
27}

1package creatures;
2public class Test {
3    public static void main(String[] args) {
4    Animal myAnimal = new Animal();
5    System.out.println("Number of legs: " + myAnimal.showLegs(4));
6    System.out.println(myAnimal.getHabitat("Forest")); // LINE 1
7    System.out.println(myAnimal.getLegs(4)); // LINE 2
8    }
9}