Quiz Space

January 2023 term · Programming Concepts using Java · BSCS2005

Java End Term: 30 April 2023, Set QPD1-S2 (January 2023 term)

The IIT Madras BS Programming Concepts using Java (Java) End Term paper sat on 30 Apr 2023, in the January 2023 term, set QPD1-S2: 23 questions for 100 marks in 180 minutes. Every question is below with its answer. Take it as a timed mock test to be marked, or read it through first.

Questions
23
Marks
100
Duration
180 min
MCQ
16
MSQ
7
Take as mock testPractise with answers

Updated

Official paper: IIT M DIPLOMA ET1 EXAM QPD1 S2 30 Apr 2023 · No negative marking.

Question 1

+4 marksOne correct option

Consider the Java code given below.

java
 1  class Example{
 2      public void functionOne(){
 3          // ...
 4          functionTwo();
 5          // ...
 6      }
 7      public void functionTwo(){
 8          // ...
 9      }
10      public static void functionThree(){
11          // ...
12          Example e = new Example();
13          e.functionOne();
14          // ...
15      }
16      public static void main(String[] args) {
17          // ...
18          functionThree();
19      }
20  }

During execution of Line 14 in the above code, the activation record of which method is at the top of the stack of activation records?

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answer

  • D
Question 1 on its own page

Question 2

+4 marksOne correct option

Consider the following code.

java
class ContactInfo implements Cloneable{
    String email;
    // Constructor
    // Accessor method getEmail()
    // Mutator method setEmail()
    public ContactInfo clone() throws CloneNotSupportedException{
        return (ContactInfo)super.clone();
    }
}
class Student implements Cloneable{
    String name;
    ContactInfo ci;
    // Constructor
    // Mutator method setName()
    public Student clone() throws CloneNotSupportedException{
        Student s = (Student)super.clone();
        s.ci = s.ci.clone();
        return s;
    }
    public String toString(){
        return  name + ":" + ci.getEmail();
    }
}
public class Test {
    public static void main(String[] args) {
        Student s1 = new Student("Rahul", new ContactInfo("mail"));
        try{
            Student s2 = s1.clone();
            s2.ci.setEmail("new mail");
            s2.setName("Sreeja");
            System.out.println(s1);
            System.out.println(s2);
        }
        catch(Exception e){
            System.out.println(e);
        }
    }
}

What will the output be?

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answer

  • A
Question 2 on its own page

Question 3

+4 marksOne correct option

Consider the code given below

java
class Shape{
    public void area(){
        System.out.println("Area exists");
    }
    public void sides(){
        System.out.println("Sides may exist");
    }
}
class Circle extends Shape{
    public void area(){
        System.out.println("Circle area");
    }
}
class Rectangle extends Shape{
    public void area(){
        System.out.println("Rectangle area");
    }
    public void sides(){
        System.out.println("Four sides");
    }
}
public class Test{
    static void display(Shape[] s){
      for(int i = 0; i < s.length; i++){
          s[i].area();
          s[i].sides();
      }
    }
    public static void main(String[] args){
        Shape[] s = {new Circle(), new Rectangle()}; // LINE 1
        display(s);
    }
}

Choose the correct option.

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answer

  • C
Question 3 on its own page

Question 4

+4 marksOne correct option

Consider the code given below that checks whether two laptops are the same. Method equals is overridden to compare two Laptop objects as follows: If two laptops have the same serial number, then they are the same. Based on the given information, answer the question that follows.

java
class Laptop{
    private String sno;


    //Constructor to initialize instance variable


    public boolean equals(Object obj) {
        // CODE BLOCK
    }
}
public class Test {
    public static void main(String[] args) {
        Laptop l1 = new Laptop("A001");
        Laptop l2 = new Laptop("A001");
        if(l1.equals(l2))
            System.out.println("l1 and l2 are the same");
        else
            System.out.println("l1 and l2 are not same");
    }
}

Choose the correct option to fill in place of CODE BLOCK so that the output is:

l1 and l2 are the same

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answer

  • B
Question 4 on its own page

Question 5

+4 marksOne correct option

Consider the Java code given below, and answer the question that follows:

java
abstract class Op implements Runnable{
    static int mul = 1;
}
class Op1 extends Op{
    public void run() {
        if (mul != 3) {
            mul = mul * 2;
        }
    }
}
class Op2 extends Op{
    public void run() {
        if (mul != 2) {
            mul = mul * 3;
        }
    }
}
public class RaceCondition {
    public static void main(String[] args) {
        Op o1 = new Op1();
        Op o2 = new Op2();


        Thread t1 = new Thread(o1);
        Thread t2 = new Thread(o2);


        t1.start();
        t2.start();


        System.out.println(Op.mul);
    }
}

Choose the correct option.

  1. A
  2. B
  3. C
  4. D
  5. E
Show answer

Correct answer

  • E
Question 5 on its own page

Question 6

+4 marksOne correct option

Consider the code given below.

java
class Rectangle{
    double length, width;
    public Rectangle(double l, double w) {
        length = l;
        width = w;
    }
    public Rectangle(Rectangle r){
        length = r.length;
        width = r.width;
    }
    public double perimeter(){
        return  2 * (length + width);
    }
}
public class ConTest {
    public static void main(String[] args) {
        Rectangle r1 = new Rectangle(6.0, 3.20);
        Rectangle r2 = new Rectangle(r1);
        Rectangle r3 = new Rectangle(r2);
        r1.width = 3.0;
        System.out.println(r1.perimeter());
        System.out.println(r2.perimeter());
        System.out.println(r3.perimeter());
    }
}

What will the output be?

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answer

  • C
Question 6 on its own page

Question 7

+4 marksOne correct option

Consider the code given below.

java
import java.util.*;
public class MapTest {
    public static void main(String[] args) {
        var bowler= new TreeMap<String,Integer>();


        bowler.put("Umran", 5);
        bowler.put("Starc", 5);


        bowler.put("Starc", 3);
        bowler.put("Umran", 3 + bowler.getOrDefault("Umran", 0));


        for(Map.Entry<String, Integer> obj1:bowler.entrySet())
            System.out.println(obj1.getKey()+":"+obj1.getValue());
    }
}

What will the output be?

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answer

  • B
Question 7 on its own page

Question 8

+4 marksOne correct option

Consider the Java code given below.

java
class InvalidIncomeException extends Exception{
    public InvalidIncomeException(String str) {
        super(str);
    }
}
class TaxPayer{
    String name;
    double income;
    public TaxPayer(String n, double i) {
        name = n;
        income = i;
    }
    public double getTax() throws InvalidIncomeException{
        if(income < 0)
            throw new InvalidIncomeException("Invalid income");
        else if(income > 700000)
            return 0.1*income;
        else
            return 0;
    }
}


public class ExceptionTest {
    public static void main(String[] args) {
        var obj1 = new TaxPayer("ABC", -700000);
        var obj2 = new TaxPayer("XYZ", 500000);
        try {
            System.out.println(obj1.getTax());
            System.out.println(obj2.getTax());
        } catch (InvalidIncomeException e) {
            System.out.println(e.getMessage());
        }
    }
}

What will the output be?

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answer

  • B
Question 8 on its own page

Question 9

+4 marksOne correct option

Consider the Java code given below.

java
import java.io.*;
class MobilePay implements Serializable{
    private String userNo = "9999999999";
    private transient int pin = 0000;
    private String upiID = "9999999999@ybl";
    public MobilePay(String uno, int p, String id) {
        userNo = uno;
        pin = p;
        upiID = id;
    }
    public String toString() {
        return userNo + ", " + pin + ", " + upiID;
    }
}
public class SerialTest{
    public static void main(String[] args) throws Exception{
        var fos = new FileOutputStream("upi.txt");
        var os = new ObjectOutputStream(fos);
        os.writeObject(new MobilePay("9977665544", 5432, "9977665544@ybl"));


        var fis = new FileInputStream("upi.txt");
        var ois = new ObjectInputStream(fis);
        MobilePay mPay = (MobilePay)ois.readObject();
        System.out.println(mPay);
    }
}

What will the output be?

  1. A
  2. B
  3. C
  4. D
  5. E
Show answer

Correct answer

  • A
Question 9 on its own page

Question 10

+4 marksOne correct option

Consider the code given below.

java
import java.util.*;
class Television{
    TreeMap<String, String> f = new TreeMap<String, String>();
    public Television() {
        f.put("LG", "Korea");
        f.put("Toshiba", "Japan");
    }
    public String getManufacturer(String t){
        return f.get(t);
    }
}
public class OptionalTest {
    public static void main(String[] args){
        Optional<String> op1 = Optional.ofNullable(new Television()
                                    .getManufacturer("Toshiba"));
        Optional<String> op2 = Optional.ofNullable(new Television()
                                    .getManufacturer("lg"));
        op1.ifPresent(n->System.out.println(n.toUpperCase()));
        op2.ifPresent(n->System.out.println(n.toUpperCase()));
    }
}

Choose the correct option.

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answer

  • D
Question 10 on its own page

Question 11

+4 marksOne correct option

Consider the code given below.

java
import java.util.*;
import java.util.stream.*;
class Student{
    String id;
    double cgpa;
    //Constructor to initialize instance variables
    //Method toString() to return id of the student
}
public class CollectingTest {
    public static void main(String[] args){
        var sArr = new ArrayList<Student>();
        sArr.add(new Student("ID6789", 9.75));
        sArr.add(new Student("ID5345", 6.75));
        sArr.add(new Student("ID4378", 8.00));
        sArr.add(new Student("ID7790", 8.45));
        Map<Boolean, List<Student>> stuMap;
        stuMap = sArr.stream()
                    .collect(Collectors.partitioningBy(s->s.cgpa >= 8.00));
        System.out.println(stuMap.get(true));
        System.out.println(stuMap.get(false));
    }
}

What will the output be?

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answer

  • C
Question 11 on its own page

Question 12

+4 marksOne correct option

Consider the code given below.
Assume that file "data.txt" exists and contains the following text.
I love my country
Assume that there is no file named "newdata.txt".

java
import java.io.*;
import java.util.Scanner;
public class FileTest {
    public static void main(String[] args) throws Exception{
        try {
            FileInputStream in = new FileInputStream("data.txt");
            Scanner sc = new Scanner(in);
            String data = "";
            if(sc.hasNext())
                data = sc.nextLine();


            var out = new FileOutputStream("newdata.txt", false);
            var dout = new DataOutputStream(out);
            dout.writeBytes(data);
            System.out.println("Data written to newdata.txt successfully");
            out.close();
            dout.close();
            sc.close();
        }
        catch (FileNotFoundException e) {
            System.out.println("File not found.....");
        }
        catch (IOException e) {
            System.out.println("Sorry there is an IO Error");
        }
    }
}

Choose the correct option regarding the code.

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answer

  • B
Question 12 on its own page

Question 13

+4 marksOne correct option

Consider the Java code given below.

java
class Triangle{
    private double base, height;
    // Constructor Triangle(double b, double h) to initialize base, height
    public double getArea() {
        assert base > 0; //LINE 1
        assert height > 0; //LINE 2
        double area = 0.5 * base * height;
        assert area > 0;  //LINE 3
        return area;
    }
}
public class AssertionTest {
    public static void main(String[] args) {
        Triangle obj = new Triangle(3.0, -4.0);
        System.out.println(obj.getArea());
    }
}

Choose the correct option when the program is executed as:
java -ea AssertionTest

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answer

  • D
Question 13 on its own page

Question 14

+4 marksOne correct option
  1. A
  2. B
  3. C
  4. D
Show answer

Correct answer

  • B
Question 14 on its own page

Question 15

+4 marksOne correct option

Consider the code given below.

java
class Example extends Thread{
    Thread t;
    Example(Thread t){
        this.t = t;
    }
    public void run(){
        try {
            t.join();
        } catch (InterruptedException ex) {


        }
        for(int i = 1; i < 3; i++){
            System.out.print(i + " ");
        }
    }
}
public class FClass{
    public static void main(String[] args) throws InterruptedException{
        Thread t1 = Thread.currentThread();
        Example t2 = new Example(t1);
        t2.start();
        for(int i = 3; i <= 5; i++){
            System.out.print(i + " ");
        }
    }
}

What will be the possible output?

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answer

  • B
Question 15 on its own page

Question 16

+5 marksOne correct option

Consider the code given below.

java
interface Chargable{
    void charge();
}
interface Supplyable{
    void supply();
}
class Bike{
    public Battery getBattery() {
        return new Battery();
    }
    private class Battery implements Chargable,Supplyable {
        public void charge() {
            System.out.println("Charges automatically while you ride");
        }
        public void supply() {
            System.out.println("Supplies current the bike requires");
        }
    }
}
public class PrivateTest {
    public static void main(String[] args) {
        //CODE BLOCK
    }
}

Choose the correct option to be filled in place of CODE BLOCK so that the output is:

Charges automatically while you ride
Supplies current the bike requires

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answer

  • D
Question 16 on its own page

Question 17

+5 marksOne or more correct options

Consider the code given below.

java
 1  interface Travelable{
 2    void travel();
 3  }
 4  interface Flyable{
 5    void fly();
 6  }
 7  interface Seatable extends Travelable, Flyable{
 8    void seat();
 9  }
10  abstract class Vehicle implements Seatable {
11    public void seat(){
12      System.out.println("Vehicle seat");
13    }
14  }
15  class Airplane extends Vehicle{
16    public void travel(){
17      System.out.println("Plane travel");
18    }
19    public void fly(){
20      System.out.println("Plane fly");
21    }
22  }
23  public class Test{
24    public static void main(String[] args){
25      Travelable t = new Airplane();
26      t.travel();
27    }
28  }

Choose the correct option/s

Select all that apply.

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answer

  • B
Question 17 on its own page

Question 18

+5 marksOne or more correct options

Consider the Java code given below that prints the recharge time of each charger in a list of chargers. From among the options, identify the appropriate function header for function display that takes as input a list of Charger objects and prints the recharge time of each.

java
import java.util.*;
abstract class Charger{
    abstract void rechargeTime();
}
class USBCharger extends Charger{
    public void rechargeTime() {
        System.out.println("USB recharge time");
    }
}
class LightiningCharger extends Charger{
    public void rechargeTime() {
        System.out.println("Lightining charger recharge time");
    }
}
public class Test {
    // LINE 1: FUNCTION HEADER
    {
        // invokes method rechargeTime()
        // to print the recharge time of each charger
    }
    public static void main(String[] args) {
        List<Charger> clist = new ArrayList<Charger>();
        clist.add(new USBCharger());
        clist.add(new LightiningCharger());
        display(clist);


    }
}

Choose the correct option(s).

Select all that apply.

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answers

  • C
  • D
Question 18 on its own page

Question 19

+5 marksOne or more correct options

Select all that apply.

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answers

  • A
  • D
Question 19 on its own page

Question 20

+5 marksOne or more correct options

Consider the code given below.

java
class Stock{
    int available = 40;
    public synchronized void request(String uname, int n){
        if(available >= n){
            available = available - n;
            System.out.println(uname + " ordered " + n + " item(s)");
        }
        else
            System.out.println(uname + " cannot order " + n + " item(s)");
    }
}
class Order implements Runnable{
    Stock st;
    String username;
    int nItems;
    public Order(Stock s, String u, int n){
        st = s;
        username = u;
        nItems = n;
    }
    public void run(){
        st.request(username, nItems);
    }
}
public class Test {
    public static void main(String[] args) {
        Stock stk = new Stock();
        Order od1 = new Order(stk, "Ram", 15);
        Order od2 = new Order(stk, "Sita", 30);
        Thread t1 = new Thread(od1);
        Thread t2 = new Thread(od2);
        t1.start();
        t2.start();
    }
}

From among the options given below, which are possible outputs of the given code?

Select all that apply.

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answers

  • A
  • D
Question 20 on its own page

Question 21

+5 marksOne or more correct options

Consider the code given below.

java
import java.util.*;
class Student{
    private String name;
    private int total;
    public Student(String n, int t) {
        name = n;
        total = t;
    }
    public int getTotal(){
        return total;
    }
    public void print() {
        System.out.println(name + " : " + total);
    }
}


public class FClass{
    public static void main(String[] args) {
        var list = new ArrayList<Student>();
        list.add(new Student("Robin", 133));
        list.add(new Student("Indra", 176));
        list.add(new Student("Smita", 135));
        list.add(new Student("Rikki", 126));
        Collections.sort(list, _____________________); // LINE 1
        for(var l: list)
            l.print();
    }
}

Identify the appropriate option(s) to fill in the blank at LINE 1, such that the output is:

Rikki : 126
Robin : 133
Smita : 135
Indra : 176

Select all that apply.

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answers

  • A
  • C
Question 21 on its own page

Question 22

+5 marksOne or more correct options

Consider the code given below.

java
public class ListExample {
    public static void main(String[] args) {
        ------------------------------- //LINE 1
        ------------------------------- //LINE 2
        list1 = new ArrayList<String>();
        list1.add("Apples");
        list1.add("Grapes");
        list2 = new LinkedList<String>(list1);
        for(String s : list1)
            System.out.println(s);
        for(String s : list2)
            System.out.println(s);
    }
}

If the code given above produces the output:

Apples
Grapes
Apples
Grapes

What should be the correct choice for LINE 1 and LINE 2?

Select all that apply.

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answers

  • B
  • C
Question 22 on its own page

Question 23

+5 marksOne or more correct options

Consider the Java code given below.

java
import java.util.*;
public class SetTest {
    public static void main(String[] args) {
        var list = new LinkedList<String>();
        list.add("Modern");
        list.add("Application");
        list.add("Development");
        list.add("Development");
        //CODE BLOCK
        for(String str:list) {
            set1.add(str);
            set2.add(str);
        }
        for(String str:set1)
            System.out.print(str+" ");
        System.out.println();
        for(String str:set2)
            System.out.print(str+" ");
    }
}

Choose the correct option(s) to be filled in place of CODE BLOCK so that the program always generates the following output:

Application Development Modern
Modern Application Development

Select all that apply.

  1. A
  2. B
  3. C
  4. D
Show answer

Correct answer

  • B
Question 23 on its own page