Java Test 2 - 2024

Q1. Given the following code:

//in file A.java
package p1;
public sealed class A permits p2.B{
}

//in file B.java
package p2;
public final class B extends p1.A{
}

Identify correct statements.

You had to select 1 option(s)

Q2. When a class, whose members should be accessible only to members of that class, is coded such a way that its members are accessible to other classes as well, this is called ...

You had to select 1 option(s)

Q3. Given:

public record Journal(int id, String name){
public Journal{ //1
id = id+1;
}

public Journal(int id, String name){ //2
this.id = id;
}
}

Identify correct statement(s).

You had to select 1 option(s)

Q4. What will the following lines of code print?

System.out.println(1 + 5 < 3 + 7);
System.out.println( (2 + 2) >= 2 + 3);

You had to select 1 option(s)

Q5. What will the following code print when compiled and run?

//imports not shown
class Movie{
static enum Genre {DRAMA, THRILLER, HORROR, ACTION };
private Genre genre;
private String name;
private char rating = 'R';
Movie(String name, Genre genre, char rating){
this.name = name; this.genre = genre; this.rating = rating;
}
//accessors not shown
}
public class FilteringStuff {
public static void main(String[] args) {
List movies = Arrays.asList(
new Movie("Titanic", Movie.Genre.DRAMA, 'U'),
new Movie("Psycho", Movie.Genre.THRILLER, 'U'),
new Movie("Oldboy", Movie.Genre.THRILLER, 'R'),
new Movie("Shining", Movie.Genre.HORROR, 'U')
);

movies.stream()
.filter(mov->mov.getRating()=='R')
.peek(mov->System.out.println(mov.getName()))
.map(mov->mov.getName());
}

}

You had to select 1 option(s)

Q6. You are the maintainer of a library packaged as bondanalytics.jar, which is used by several groups in your company. It has the following two packages that are used by other applications:

com.abc.bonds
com.abc.bonds.analytics

You want to modularize this jar with least impact to others. What will you do?

You had to select 1 option(s)

Q7. Given:

class A extends Thread
{
boolean flag = true;
public void run()
{
System.out.println("Starting loop");

while( flag ){ }; //1

System.out.println("Ending loop");
}
}
public class TestClass
{
public static void main(String args[]) throws Exception
{
A a = new A();
a.start();
Thread.sleep(1000);

//2

}
}

Idenfity correct statements about the above program.

You had to select 1 option(s)

Q8. Following is a program to capture words from command line and create two collections. One that keeps only unique words and one that keeps all the words in the order they were entered. What should replace AAA and BBB?

static Collection unique = new AAA();
static Collection ordered = new BBB();
public static void main(String args[]) throws Exception
{
BufferedReader bfr = new BufferedReader( new InputStreamReader( System.in ) );
String s = bfr.readLine();
while(s != null && s.length() >0)
{
unique.add(s);
ordered.add(s);
s = bfr.readLine();
}
System.out.println(unique);
System.out.println(ordered);
}

You had to select 2 option(s)

Q9. Given:

public class LoopTest {
int k = 5;
public boolean checkIt(int k){
return k-->0?true:false;
}
public void printThem(){
while(checkIt(k)){
System.out.print(k);
}
}
public static void main(String[] args) {
new LoopTest().printThem();
}
}

What changes should be made so that the program will print 54321?

You had to select 1 option(s)

Q10. What will the following code print when compiled and run?

You had to select 1 option(s)

Q11. Consider the following program...

class ArrayTest{
public static void main(String[] args){
var ia[][] = { {1, 2}, null };
for (int i = 0; i < 2; i++)
for (int j = 0; j < 2; j++)
System.out.println(ia[i][j]);
}
}

Which of the following statements are true?

You had to select 1 option(s)

Q12.Which of the following are valid declarations inside an interface independent of each other?

You had to select 2 option(s)

Q13. What will the following code snippet print?

int index = 1;
String[] strArr = new String[5];
var myStr = strArr[index];
System.out.println(myStr);

You had to select 1 option(s)

Q14. You are working on an application that is NOT structured as a modular application. However, you need to use a third party library that is packaged as a modular jar named abc.utils.jar in your application.

Given that you launch your application using a class named Main, which of the following options should be used to make sure your application is able to access the classes in the third party jar?
(Assume that abc.utils.jar and your application classes are in current directory.)

You had to select 1 option(s)

Q15. Identify correct statements above the following code:

var myES = Executors.newSingleThreadExecutor();
myES.submit(() -> {}); //1
myES.submit(() -> 100);//2

You had to select 2 option(s)

Q16. Assuming that the following method will always be called with a phone number in the format ddd-ddd-dddd (where d stands for a digit), what can be inserted at //1 so that it will return a String containing the same number except its last four digits will be masked with xxxx?

public static String hidePhone(String fullPhoneNumber){
//1 Insert code here
}

You had to select 3 option(s)

Q17. Consider the following code:

class Super { static String ID = "QBANK"; }

class Sub extends Super{
static { System.out.print("In Sub"); }
}
public class Test{
public static void main(String[] args){
System.out.println(Sub.ID);
}
}

What will be the output when class Test is run?

You had to select 1 option(s)

Q18. What will be the output when the following program is run?

package exceptions;
public class TestClass{
public static void main(String[] args) {
try{
hello();
}
catch(MyException me){
System.out.println(me);
}
}

static void hello() throws MyException{
int[] dear = new int[7];
dear[0] = 747;
foo();
}

static void foo() throws MyException{
throw new MyException("Exception from foo");
}
}

class MyException extends Exception {
public MyException(String msg){
super(msg);
}
}

(Assume that line numbers printed in the messages given below are correct.)

You had to select 1 option(s)

Q19. Consider the following method code:

public static void copy(String records1, String records2) {
try (
InputStream is = new FileInputStream(records1);
OutputStream os = new FileOutputStream(records2); ) {

byte[] buffer = new byte[1024];
int bytesRead = 0;
while ((bytesRead = is.read(buffer)) != -1) {
os.write(buffer, 0, bytesRead);
System.out.println("Read and written bytes " + bytesRead);
}
}
catch ( *INSERT CODE HERE* e ) { //LINE 100
}

}

What can be inserted at //LINE 100 to make the method compile?

You had to select 1 option(s)

Q20. Given:

public class TestClass
{
public static void main(String args[])
{
B b = new C();
A a = b;
if (a instanceof B b1) b1.b();
if (a instanceof C c1) c1.c();
if (a instanceof D d1) d1.d();
}
}
class A {
void a(){ System.out.println("a"); }
}
class B extends A {
void b(){ System.out.println("b"); }
}
class C extends B {
void c(){ System.out.println("c"); }
}
class D extends C {
void d(){ System.out.println("d"); }
}

What is the result?

You had to select 1 option(s)

Q21. What will the following program print?

public class TestClass{
static String str = """
Hello World""";
public static void changeIt(String s){
s = "Good bye world";
}
public static void main(String[] args){
changeIt(str);
System.out.println(str);
}
}

You had to select 1 option(s)

Q22. Given:

class Person{
private String name;
private int age;
public Person(String name, int age){
this.name = name;
this.age = age;
}
//getters/setters not shown
}

What will the following code print?

List friends = Arrays.asList(new Person("Bob", 31),
new Person("Paul", 32),
new Person("John", 33));
double averageAge = friends.stream().filter(f->f.getAge()<30)
.mapToInt(f->f.getAge())
.average().getAsDouble();
System.out.println(averageAge);

You had to select 1 option(s)

Q23, Given:

public class Book {
private String title;
private String genre;
public Book(String title, String genre){
this.title = title; this.genre = genre;
}
//accessors and toString code not shown
}

and the following code:

var books = new ArrayList(List.of(new Book("The Outsider", "fiction"),
new Book("Becoming", "non-fiction"),new Book("Uri", "non-fiction")));

books.sort(Comparator.comparing(Book::getGenre)
.thenComparing(Book::getTitle).reversed());
System.out.println(books);

What will be the result?

You had to select 1 option(s)

Q24. Consider the following code:

import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
public class MyCache {
private CopyOnWriteArrayList cal = new CopyOnWriteArrayList();

public void addData(List list){
cal.addAll(list);
}

public Iterator getIterator(){
return cal.iterator();
}
}


Given that one thread calls the addData method on an instance of the above class and another thread calls the getIterator method on the same instance at the same time and starts iterating through its values, which of the following options are correct?

(Assume that no other calls have been made on the MyCache instance.)

You had to select 1 option(s)

Q25. Consider the following method:

static int mx(int s){
for(int i=0; i<3; i++){
s = s + i;
}
return s;
}

and the following code snippet:

int s = 5;
s += s + mx(s) + ++s;
System.out.println(s);

What will it print?

You had to select 1 option(s)

Q26. What can be inserted at line 2 in the code snippet given below?

String[] names = {"Alex", "Bob", "Charlie" };
//Insert code here
System.out.println(list.get(0));

You had to select 2 option(s)

Q27. What will the following code print when compiled and run?

Stream values = IntStream.rangeClosed(10, 15).boxed(); //1
Object obj = values.collect(Collectors.partitioningBy(x->x%2==0)); //2
System.out.println(obj);

You had to select 1 option(s)

Q28. Given:

//creating Book objects using Book(String title, String author) constructor
var books = List.of(new Book("The Outsider", "Stephen King"),
new Book("The Shining", "Stephen King" ), new Book("Uri", "India"));
Stream bkStrm = books.stream();//

long count = *INSERT CODE HERE*;
System.out.println(count);


Assuming Book class has appropriate constructor and accessor methods, which of the following statements will correctly print the number of unique authors in the list of Books?

You had to select 1 option(s)

Q29. What will the following code print when compiled and run?

import java.util.*;
public class TestClass {
public static void main(String[] args) throws Exception {
List list = new ArrayList();
list.add("val1"); //1
list.add(2, "val2"); //2
list.add(1, "val3"); //3
System.out.println(list);
}
}

You had to select 1 option(s)

Q30. Which of the following statements would you need to have in the module-info of a Java Swing based desktop application?

You had to select 1 option(s)

Q31. Given:

abstract class Base{
abstract int power();
}

class A extends Base{
@Override
int power(){ return 0; }
}

public class TestClass
{

static void processBase(Base base){
A a = null;
if(base instanceof A a ){
System.out.println(a.power());
}
System.out.println("a is "+a);
}

public static void main(String args[])
{
processBase(new A());
}
}


What is the result?

You had to select 1 option(s)

Q32. Consider the following code:

public class TestClass {

public static void doStuff() throws Exception{
System.out.println("Doing stuff...");
if(Math.random()>0.4){
throw new Exception("Too high!");
}
System.out.println("Done stuff.");
}

public static void main(String[] args) throws Exception {
doStuff();
System.out.println("Over");
}
}

Which of the following are possible outputs when the above program is compiled and run?

(Assume that Math.random() returns a double between 0.0 and 1.0 not including 1.0.
Further assume that there is no mistake in the line numbers printed in the output shown in the options.)

You had to select 2 option(s)

Q33. What will the following code print when run?

Deque d = new ArrayDeque();
d.push(1);
d.push(2);
d.push(3);
System.out.println(d.pollFirst());
System.out.println(d.poll());
System.out.println(d.pollLast());

You had to select 1 option(s)

Q34. Consider the following classes :

class A{
public void mA(){ };
}

class B extends A {
public void mA(){ }
public void mB() { }
}

class C extends B {
public void mC(){ }
}
and the following declarations:
A x = new B(); B y = new B(); B z = new C();
Which of the following calls are virtual calls?

You had to select 3 option(s)

Q35. A java programer has written the following code:

public class Book {
private int id;
private String title;
private String genre;
private String author;

public Book(String title, String genre, String author){
this.title = title; this.genre = genre; this.author = author;
}

//accessors for instance fields not shown here

public static class BookFilter {
public boolean isFiction(Book b){
return b.getGenre().equals("fiction");
}

}
}

He wants to make use of the above code in another class as follows -

List books = Arrays.asList(new Book("30 Days", "fiction", "K Larsen"),
new Book("Fast Food Nation", "non-fiction", "Eric Schlosser"),
new Book("Wired", "fiction", "D Richards"));

books.stream()

.filter(new Book.BookFilter()) //LINE 10

.forEach((Book b) -> System.out.print(b.getTitle()+", "));

What changes mentioned below can he make independent of each other so that the above code will print 30 Days, Wired, ?

You had to select 2 option(s)

Q36. Given:

class Square {
private double side = 0;
String color;
public Square(double length){
this.side = length;
}
public double getSide() { return side; }

public void setSide(double side) { this.side = side; }

}

public class TestClass {
public static void main(String[] args) throws Exception {
Square mysq = new Square(10);
mysq.color = "red";

//set mysq's side to 20
}
}

Which of the following statements will set the side of Square object referred by mysq to 20?

You had to select 1 option(s)

Q37. Identify correct statements about the module system of Java.

You had to select 3 option(s)

Q38. Given:

public class Book {
private String title;
private String genre;
public Book(String title, String genre){
this.title = title; this.genre = genre;
}

//accessors not shown
}

and the following code:

List books = //code to create the list goes here

Comparator c1 = (b1, b2)->b1.getGenre().compareTo(b2.getGenre()); //1
books.stream().sorted(c1.thenComparing(Book::getTitle)); //2
System.out.println(books);

Identify the correct statements.

You had to select 1 option(s)

Q39. Which of the following class definitions is/are legal definition(s) of a class that cannot be instantiated?

class Automobile{
abstract void honk(); //(1)
}

abstract class Automobile{
void honk(); //(2)
}

abstract class Automobile{
void honk(){}; //(3)
}

abstract class Automobile{
abstract void honk(){} //(4)
}

abstract class Automobile{
abstract void honk(); //(5)
}

You had to select 2 option(s)

Q40. Given:

var nums = List.of(1, 2, 3, 4, 5, 6, 7).stream();

Predicate p = //a predicate goes here

Optional value = nums.filter(p).reduce((a, b)->a+b);
value.ifPresent(System.out::println);

You had to select 2 option(s)

Q41. Assuming that STOCK table exists and is empty, what will the following code snippet print?

Assume that EXCHANGE column allows null values.

You had to select 1 option(s)

Q42. Which of the following code snippets will compile without any errors?

(Assume that the statement int x = 0; exists prior to the statements below.)

You had to select 3 option(s)

Q43. Consider the following code:

class Bond
{
String ticker; double coupon; java.time.LocalDate maturity;
}

class Portfolio implements Serializable
{
String accountName;
Bond[] bonds;
}

public class TestClass {
public static void main(String[] args) throws Exception{
Portfolio portfolio = // get portfolio somehow
// serialize portfolio
}
}

Which of the following approaches can be taken independent of each other so that a Portfolio object can be serialized while preserving the state of the Bond objects contained in Portfolio?

You had to select 2 option(s)

Q44. Which of the following lines will cause the compilation to fail??

(Assume that all of the following code is in one file.)


public enum EnumA{ A, AA, AAA}; //1

public class TestClass //2
{
public enum EnumB{ B, BB, BBB }; //3
public static enum EnumC{ C, CC, CCC }; //4
public TestClass()
{
enum EnumD{ D, DD, DDD } //5
}

public void methodX()
{
public enum EnumE{ E, EE, EEE } //6
}

public static void main(String[] args) //7
{
enum EnumF{ F, FF, FFF}; //8
}
}

You had to select 2 option(s)

Q45. How can you fix the following code to make it compile:

import java.io.*;
class Great {
public void doStuff() throws FileNotFoundException{
}
}

class Amazing extends Great {
public void doStuff() throws IOException, IllegalArgumentException{
}
}

public class TestClass {
public static void main(String[] args) throws IOException{
Great g = new Amazing();
g.doStuff();
}
}

Assume that changes suggested in a option are to be applied independently of changes suggested in other options.

You had to select 2 option(s)

Q46. Consider the following code:

class LowBalanceException extends _______ { //1
public LowBalanceException(String msg){ super(msg); }
}

class WithdrawalException extends _______ { //2
public WithdrawalException(String msg){ super(msg); }
}
class Account{
double balance;
public void withdraw(double amount) throws WithdrawalException{
try{
throw new RuntimeException("Not Implemented");
}catch(Exception e){
throw new LowBalanceException(e.getMessage());
}
}
public static void main(String[] args) {
try{
Account a = new Account();
a.withdraw(100.0);
}catch(Exception e){
System.out.println(e.getMessage());
}
}
}

What can be inserted at //1 and //2 so that the above code will prints Not Implemented?.

You had to select 1 option(s)

Q47. Given the following code, which of these statements are true?

class TestClass{
public static void main(String args[]){
int k = 0;
int m = 0;
for ( var i = 0; i <= 3; i++){
k++;
if ( i == 2){
// line 1
}
m++;
}
System.out.println( k + ", " + m );
}
}

You had to select 3 option(s)

Q48. Consider the following code:

package jqplus;
import java.util.*;

public class Testclass {

public static void main(String[] args) {

NavigableMap mymap = new TreeMap();
mymap.put("a", "apple"); mymap.put("b", "boy"); mymap.put("c", "cat");
mymap.put("aa", "apple1"); mymap.put("bb", "boy1"); mymap.put("cc", "cat1");

mymap.pollLastEntry(); //LINE 1
mymap.pollFirstEntry(); //LINE 2

NavigableMap tailmap = mymap.tailMap("bb", false); //LINE 3

System.out.println(tailmap.pollFirstEntry()); //LINE 4
System.out.println(mymap.size()); //LINE 5

}
}

What will be returned by the call to tailmap.pollFirstEntry() at //LINE 4 and mymap.size() at //LINE 5?

You had to select 1 option(s)

Q49. Given:

public class Student {
public static enum Grade{ A, B , C, D, F}

private String name;
private Grade grade;
public Student(String name, Grade grade){
this.name = name;
this.grade = grade;
}
public String toString(){
return name+":"+grade;
}
//getters and setters not shown
}

What can be inserted in the code below so that it will print:
{C=[S3:C], A=[S1:A, S2:A]}


List ls = Arrays.asList(
new Student("S1", Student.Grade.A), new Student("S2", Student.Grade.A),
new Student("S3", Student.Grade.C));
//INSERT CODE HERE
System.out.println(grouping);

You had to select 1 option(s)

Q50. Given the following class code:

public class Transfer implements Runnable{
Account from, to;
double amount;
public Transfer(Account from, Account to, double amount){
this.from = from; this.to = to; this.amount = amount;
}
public void run(){
synchronized(from){
from.setBalance(from.getBalance()-amount);
synchronized(to){
to.setBalance(to.getBalance()+amount);
}
}
}
}

Relevant code for the Account class referred above is as follows:
public class Account{
private String id; private double balance;
//constructor and accessor methods not shown,
}


What will happen when the following code is executed?


var es = Executors.newCachedThreadPool();
var a1 = new Account("A1", 1000);
var a2 = new Account("A1", 1000);
es.submit(new Transfer(a1, a2, 200));
es.submit(new Transfer(a2, a1, 300));

You had to select 1 option(s)

Q51. What will be the result of attempting to compile and run the following program?

class TestClass{
public static void main(String args[]){
int i = 0;
loop : // 1
{
System.out.println("Loop Lable line");
try{
for ( ; true ; i++ ){
if( i >5) break loop; // 2
}
}
catch(Exception e){
System.out.println("Exception in loop.");
}
finally{
System.out.println("In Finally"); // 3
}
}
}
}

You had to select 1 option(s)

Q52. What will the following code snippet print when compiled and run?

byte starting = 3;
short firstValue = 5;
int secondValue = 7;
int functionValue = (int) (starting/2 + firstValue/2 + (int) firstValue/3 )
+ secondValue/2;
System.out.println(functionValue);

You had to select 1 option(s)

Q53. Which of the following are valid declarations independent of each other inside the following interface?

public interface FooI{

}

You had to select 4 option(s)

Q54. Identify correct statements about the following code:

interface Processor {
Iterable process();
}

interface ItemProcessor extends Processor{
Collection process();
}

interface WordProcessor extends Processor{
String process();
}

interface GenericProcessor extends ItemProcessor, WordProcessor{

}

You had to select 2 option(s)

Q55. Given that a class named com.xyz.fx.Main is part of a module named xyz.fx packaged in fx.jar, which of the following commands can be used to execute this class?

(Assume that the jar file is located in the current directory.)

You had to select 2 option(s)