Question 1

1import java.util.*;
2interface Vehicle {
3    void start();
4}
5class Car implements Vehicle {
6    public void start() {
7        System.out.println("Starting a Car");
8    }
9}
10class Motorcycle implements Vehicle {
11    public void start() {
12        System.out.println("Starting a Motorcycle");
13    }
14}
15class Garage<T extends Vehicle> {
16    private Map<String, T> vehicles;
17    public Garage() {
18        vehicles = new LinkedHashMap<String, T>();//LINE A
19    }
20
21    public void add(String name, T vehicle) {
22        vehicles.put(name, vehicle);
23    }
24    public void startVehicle(String name) {
25        if (vehicles.containsKey(name)) {
26            T v = vehicles.get(name); //LINE B
27            v.start();
28        } else {
29            System.out.println("Vehicle not found");
30        }
31    }
32}
33public class TestGarage {
34    public static void main(String[] args) {
35        Garage<Vehicle> g = new Garage<Vehicle>();
36        Vehicle v1 = new Car();
37        Vehicle v2 = new Motorcycle();
38        g.add("car", v1);
39        g.add("motorcycle", v2);
40        g.startVehicle("car");
41        g.startVehicle("bicycle");
42    }
43}

Consider the Java code given below. The method boolean containsKey (Object key) in the class Map returns true if and only if the map contains an entry for a key k such that Objects.equals(key, k). import java.util.*; interface Vehicle { void start(); } class Car implements Vehicle { public void start() { System.out.println("Starting a Car"); } } class Motorcycle implements Vehicle { public void start() { System.out.println("Starting a Motorcycle"); } } class Garage<T extends Vehicle> { private Map<String, T> vehicles; public Garage() { vehicles = new LinkedHashMap<String, T>();//LINE A } public void add(String name, T vehicle) { vehicles.put(name, vehicle); } public void startVehicle(String name) { if (vehicles.containsKey(name)) { T v = vehicles.get(name); //LINE B v.start(); } else { System.out.println("Vehicle not found"); } } } public class TestGarage { public static void main(String[] args) { Garage<Vehicle> g = new Garage<Vehicle>(); Vehicle v1 = new Car(); Vehicle v2 = new Motorcycle(); g.add("car", v1); g.add("motorcycle", v2); g.startVehicle("car"); g.startVehicle("bicycle"); } } Choose the correct option. Consider two Java files located in two different packages as shown below. Vehicle.java: package com.transport; public class Vehicle { void startEngine() { System.out.println("Engine started"); } private void stopEngine() { System.out.println("Engine stopped"); } protected void accelerate() { System.out.println("Accelerating"); } public void brake() { System.out.println("Braking"); } } Car.java package com.automobile; import com.transport.Vehicle; public class Car extends Vehicle { public static void main(String[] args) { Car car = new Car(); car.startEngine(); // LINE A car.stopEngine(); // LINE B car.accelerate(); // LINE C car.brake(); // LINE D } } Choose the correct option. Consider the Java code given below. class NewUser{ private String name, password; public NewUser(String s, String p) { this.name = s; this.password = p; } public String getUserName() { assert name != null : "Invalid name"; //LINE 1 assert password.length() == 10 : "Should be 10 characters"; //LINE 2 return name + "@acct.com"; } } public class Test { public static void main(String[] args) { NewUser u1 = new NewUser("", "password"); NewUser u2 = new NewUser("Sudarshan", "1234567890"); String username1 = u1.getUserName(); //LINE 3 assert username1 != null : "Should not be null"; // LINE 4 String username2 = u2.getUserName(); //LINE 5 assert username2 != null : "Should not be null"; // LINE 6 System.out.println(username1); System.out.println(username2); } } Choose the correct option when the program is executed as:\ java -ea Test