Advanced Java Practice Test: Prepare for Certification in 2024

Q1. What should be placed in the two blanks so that the following code will compile without errors:

class XXX{
public void m() {
throw new RuntimeException();
}
}
class YYY extends XXX{
public void m() throws Exception{
throw new Exception();
}
}
public class TestClass {
public static void main(String[] args) {
______ obj = new ______();
obj.m();
}
}

You had to select 1 option(s)

Q2. What will the following code fragment print when compiled and run?

Locale myloc = new Locale.Builder().setLanguage("hinglish")
.setRegion("IN").build(); //L1
ResourceBundle msgs = ResourceBundle.getBundle("mymsgs", myloc);

Enumeration en = msgs.getKeys();
while(en.hasMoreElements()){
String key = en.nextElement();
String val = msgs.getString(key);
System.out.println(key+"="+val);
}

Assume that only the following two properties files (contents of the file is shown below the name of the file) are accessible to the code.

1. mymsgs_hinglish_US.properties
okLabel=OK
cancelLabel=Cancel

2. mymsgs_hinglish_UK.properties
okLabel=YES
noLabel=NO

You had to select 1 option(s)

Q3. Given:

class Item{
private int id;
private String name;
public Item(int id, String name){
this.id = id;
this.name = name;
}
public Integer getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}
public String toString(){
return name;
}
}


public class Test {
public static void main(String[] args) {
List l = Arrays.asList(
new Item(1, "Screw"),
new Item(2, "Nail"),
new Item(3, "Bolt")
);

l.stream()
//INSERT CODE HERE
.forEach(System.out::print);
}
}

Which of the following options can be inserted in the above code independent of each other, so that the code will print BoltNailScrew?

You had to select 2 option(s)

Q4. Given the following code:

//in WeekDay.java
package days;
public sealed class WeekDay permits Monday {
}

Which of the following is a valid declaration of Monday?

You had to select 1 option(s)

Q5. Given:

//assume appropriate imports
public class Calculator{
public static void main(String[] args) {
double principle = 100;
int interestrate = 5;
double amount = compute(principle, x->x*interestrate);
}

INSERT CODE HERE
}

Which of the following methods can be inserted in the above code so that it will compile and run without any error/exception?

You had to select 2 option(s)

Q6. Given:

Locale locale = new Locale("en", "US");
ResourceBundle rb = ResourceBundle.getBundle("test.MyBundle", locale);

Which of the following are valid lines of code?
(Assume that the ResourceBundle has the values for the given keys.)

You had to select 2 option(s)

Q7. Identify correct statements about the modular system of Java.

You had to select 3 option(s)

Q8. What will happen when the following code is compiled and run?

class AX{
static int[] x = new int[0];
static{
x[0] = 10;
}
public static void main(String[] args){
var ax = new AX();
}
}

You had to select 1 option(s)

Q9. Which of the following are valid declarations inside an interface independent of each other?

You had to select 3 option(s)

Q10. What will the following code print when run?

public class TestClass{
public static Integer wiggler(Integer x){
Integer y = x + 10;
x++;
System.out.println(x);
return y;
}

public static void main(String[] args){
Integer dataWrapper = Integer.valueOf(5);
Integer value = wiggler(dataWrapper);
System.out.println(dataWrapper+value);
}
}

You had to select 1 option(s)

Q11. What will be the result of attempting to compile and run the following class?

public class InitTest{
static String s1 = sM1("a");{
s1 = sM1("b");
}
static{
s1 = sM1("c");
}
public static void main(String args[]){
InitTest it = new InitTest();
}
private static String sM1(String s){
System.out.println(s); return s;
}
}

You had to select 1 option(s)

Q12. Given:

public static void copy1(Path p1, Path p2) throws Exception {
Files.copy(p1, p2, StandardCopyOption.REPLACE_EXISTING);
}


Identify correct statements.

You had to select 2 option(s)

Q13. Consider the following code:

class Account{
private String id; private double balance;

ReentrantLock lock = new ReentrantLock();

public void withdraw(double amt){
try{
lock.lock();
if(balance > amt) balance = balance - amt;
}finally{
lock.unlock();
}
}
}

What can be done to make the above code thread safe?

You had to select 1 option(s)

Q14. Given the following code:

package com.auto.vehicles;
public interface Drivable{
void drive();
}

and

package com.auto.vehicles.electric;
public class ECar implements Drivable{
private int maxSpeed;
public ECar(){
this(120);
}
public ECar(int maxSpeed){
this.maxSpeed = maxSpeed;
}

@Override
public void drive(){
System.out.println("driving ecar");
}
}


Which statements should be present in the module-info for it to represent a service provider?

You had to select 2 option(s)

Q15. Consider the following class...

public class ParamTest {

public static void printSum(double a, double b){
System.out.println("In double "+(a+b));
}

public static void printSum(float a, float b){
System.out.println("In float "+(a+b));
}

public static void main(String[] args) {
printSum(1, 2.0);
printSum(1, 2);
printSum(1.0, 2.0);
}
}

What will be printed?

You had to select 1 option(s)

Q16. What will the following code print?

String s = "blooper";
StringBuilder sb = new StringBuilder(s);
sb.append(s.substring(4)).delete(3, 5);
System.out.println(sb);

You had to select 1 option(s)

Q17. Consider the following method:

public void setSQLMode(Connection c, String mode) throws Exception{
Statement stmt = c.createStatement();
String qr = "SET SESSION sql_mode = '"+mode+"';";
stmt.execute(qr);
}

Identify the correct statement about the above code.

You had to select 1 option(s)

Q18. Given:

public class CrazyMath {
public static void main(String[] args) {
int x = 10, y = 20;
int dx, dy;
try{
dx = x % 5;
dy = y/dx;
}catch(ArithmeticException ae){
System.out.println("Caught AE");
dx = 2;
dy = y/dx;
}
x = x/dx;
y = y/dy;
System.out.println(dx+" "+dy);
System.out.println(x+" "+y);

}
}

What is the output?

You had to select 1 option(s)

Q19. Identify correct statement(s) regarding the benefit of using PreparedStatement over Statement.

You had to select 2 option(s)

Q20. Which of the following method implementations will write a boolean value to the underlying stream?

You had to select 3 option(s)

Q21. Consider the following code snippet :

public void readData(String fileName) throws Exception {
try(FileReader fr1 = new FileReader(fileName)){
Connection c = getConnection();
//...other valid code
}
}

Given that the call to getConnection method in the above code throws a ClassNotFoundException and that an IOException is thrown while closing fr1, which exception will be received by the caller of readData() method?

You had to select 1 option(s)

Q22. What letters, and in what order, will be printed when the following program is compiled and run?

public class FinallyTest{
public static void main(String args[]) throws Exception{
try{
m1();
System.out.println("A");
}
finally{
System.out.println("B");
}
System.out.println("C");
}
public static void m1() throws Exception { throw new Exception(); }
}

You had to select 1 option(s)

Q23. What can be done to get the following code to compile and run? (Assume that the options are independent of each other.)

public float parseFloat( String s ){
float f = 0.0f; // 1
try{
f = Float.valueOf( s ).floatValue(); // 2
return f ; // 3
}
catch(NumberFormatException nfe){
f = Float.NaN ; // 4
return f; // 5
}
finally {
return f; // 6
}
return f ; // 7
}

You had to select 4 option(s)

Q24. The following code was written for Java 7:

Map groupedValues = new HashMap();

public void process(String name, Double value){
List values = groupedValues.get(name);
if(values == null){
values = new ArrayList();
groupedValues.put(name, values);
}
values.add(value);
}

Which of the following implementations correctly makes use of the functional interfaces available in the Java standard library to achieve the same?

You had to select 1 option(s)

Q25. Given:

module broker{
exports org.broker.api;
provides org.broker.api.Broker with org.broker.api.MyBroker
}

Which of the following statements are correct?

You had to select 3 option(s)

Q26. Consider the following hierarchy of Exception classes :

java.lang.RuntimeException
+----- IndexOutOfBoundsException
+----ArrayIndexOutOfBoundsException, StringIndexOutOfBoundsException

Which of the following statements are correct for a method that can throw ArrayIndexOutOfBounds as well as StringIndexOutOfBounds Exceptions but does not have try catch blocks to catch the same?

You had to select 3 option(s)

Q27. A modularized application has been packaged in graphs.jar file with module name as com.xcomp.graphs. The entry point of the application is a class named Main in package com.xcomp.graphs.

Which two options can be used to execute this application?

You had to select 2 option(s)

Q28. Identify correct statements about the following code -

interface Drink{
default double getAlcoholPercent(){
return 0.0;
}

static double computeAlcoholPercent(){
return 0.0;
}
}


interface ColdDrink extends Drink{
String getName();
}

class CrazyDrink implements ColdDrink{
// INSERT CODE HERE
}

You had to select 1 option(s)

Q29. What will the following code print?

Object v1 = IntStream.rangeClosed(10, 15)
.boxed()
.filter(x->x>12)
.parallel()
.findAny();

Object v2 = IntStream.rangeClosed(10, 15)
.boxed()
.filter(x->x>12)
.sequential()
.findAny();

System.out.println(v1+":"+v2);

(Note: in the options below denote the possible output and not the sign themselves.)

You had to select 1 option(s)

Q30. Given the following code :

public class TestClass {

int[][] matrix = new int[2][3];

int[] a = new int[]{1, 2, 3};
int[] b = new int[]{4, 5, 6};

public int compute(int x, int y){
//1 : Insert Line of Code here
}

public void loadMatrix(){
for(int x=0; xfor(int y=0; y//2: Insert Line of Code here
}
}
}
}

What can be inserted at //1 and //2?

You had to select 1 option(s)

Q31. What will the following code print when run without any arguments ...

public class TestClass {

public static int m1(int i){
return ++i;
}

public static void main(String[] args) {

int k = m1(args.length);
k += 3 + ++k;
System.out.println(k);
}

}

You had to select 1 option(s)

Q32. What will the following program print?

public class TestClass{
static int someInt = 10;
public static void changeIt(int a){
a = 20;
}
public static void main(String[] args){
changeIt(someInt);
System.out.println(someInt);
}
}

You had to select 1 option(s)

Q33. Given:

public class ItemProcessor implements Runnable{ //LINE 1
CyclicBarrier cb;
public ItemProcessor(CyclicBarrier cb){
this.cb = cb;
}
public void run(){
System.out.println("processed");
try {
cb.await();
} catch (Exception ex) {
ex.printStackTrace();
}
}
}

public class Merger implements Runnable{ //LINE 2
public void run(){
System.out.println("Value Merged");
}
}

What should be inserted in the following code such that run method of Merger will be executed only after the thread started at 4 and the main thread have both invoked await?

public static void main(String[] args) throws Exception{
var m = new Merger();

//LINE 3

var ip = new ItemProcessor(cb);
ip.start(); //LINE 4
cb.await();
}

You had to select 1 option(s)

Q34. What will the following code print when run?

String[] sa = { "charlie", "bob", "andy", "dave" };
Collections.sort(Arrays.asList(sa), null);
System.out.println(sa[0]);

You had to select 1 option(s)

Q35. What will the following code print when compiled and run:

public class TestClass {

public static void main(String[] args){
while(var k = 5; k<7){
System.out.println(k++);
}
}
}

You had to select 1 option(s)

Q36. Given:

int[][] iaa = { {1, 2}, {3, 4}, { 5, 6} };
long count = Stream.of(iaa).flatMapToInt(IntStream::of)
.map(i->i+1).filter(i->i%2 != 0).peek(System.out::print).count();
System.out.println(count);

What will be the output?

You had to select 1 option(s)

Q37. What will be the result of compiling and running the following code:

float foo = 2, bar = 3, baz = 4; //1
float mod1 = foo % baz, mod2 = baz % foo; //2
float val = mod1>mod2? bar : baz; //3
System.out.println(val);

You had to select 1 option(s)

Q38. Given the following code:

Locale.setDefault(Locale.ITALY);
Locale loc = new Locale.Builder().setLanguage("en").build();
ResourceBundle rb = ResourceBundle.getBundle("mymsgs", loc);
System.out.println(rb.getString("helloMsg"));

and the following properties files:
mymsgs.properties
mymsgs_en_IT.properties
mymsgs_en.properties
mymsgs_IT.properties

Which of the following statements are correct?

You had to select 2 option(s)

Q39. 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 = List.of(
new Book("Gone with the wind", "Fiction"),
new Book("Bourne Ultimatum", "Thriller"),
new Book("The Client", "Thriller")
);

Reader r = b->{
System.out.println("Reading book "+b.getTitle());
};
books.forEach(x->r.read(x));

What would be a valid definition of Reader for the above code to compile and run without any error or exception?

You had to select 2 option(s)

Q40. Which of the following code fragments compile without any error?

You had to select 3 option(s)

Q41. Consider the following code:

class Base{
private float f = 1.0f;
void setF(float f1){ this.f = f1; }
}
class Base2 extends Base{
private float f = 2.0f;
//1
}

Which of the following options is/are valid example(s) of overriding?

You had to select 2 option(s)

Q42. Given:

Stream strm1 = Stream.of(2, 3, 5, 7, 11, 13, 17, 19); //1
Stream strm2 = strm1.filter(i->{ return i>5 && i<15; }); //2
strm2.forEach(System.out::print); //3


Which of the following options can be used to replace line at //2 and still print the same elements of the stream?

You had to select 1 option(s)

Q43. What will be the output?

var ca = new char[]{'a', 'b', 'c', 'd'};
var i = 0;
for(var c : ca){
switch(c){
case 'a' : i++;
case 'b' : ++i;
case 'c'|'d' : i++;
}
}

System.out.println("i = "+i);

You had to select 1 option(s)

Q44. What will the following class print when run?

public class Sample{
public static void main(String[] args) {
String s1 = """
java \
java\
""";
StringBuilder s2 = new StringBuilder("news");
s1.replace("java", "");
s2.append(s1);
System.out.println(s2.indexOf("java"));
}
}

You had to select 1 option(s)

Q45. How will you initialize a DateTimeFormatter object so that the following code will print the number of the month (i.e. 02 for Feb, 12 for Dec, and so on) and a two digit calendar year of any given date?

System.out.println(dtf.format(LocalDate.now()));

You had to select 1 option(s)

Q46. Which of the following can be valid declarations of an integer variable?

You had to select 2 option(s)

Q47. Which of the following statements are true?

You had to select 2 option(s)

Q48. Which of the following implementations of a max() method will correctly return the largest value?

You had to select 1 option(s)

Q49. Which of the following statements correctly obtains a reference to a Console object?

You had to select 1 option(s)

Q50. Given:

public class SimpleLoop {
public static void main(String[] args) {
int i=0, j=10;
while (i<=j) {
i++;
j--;
}
System.out.println(i+" "+j);
}
}

What is the result?

You had to select 1 option(s)

Q51. Given:

sealed interface Member permits Student, Person{ //LINE A
String role();
}

record Person(String role) implements Member{ //LINE B
}

record Student(int id, Person person) //LINE C
implements Member //LINE D
{
public String role(){ return person.role(); } //LINE E
}


Which lines will cause compilation issues?

You had to select 1 option(s)

Q52. Given:

class T extends Thread
{
static Lock lock = new ReentrantLock();

public T(String name){ super(name); }

public void run()
{
for(int i=0; i<2; i++){
if(lock.tryLock()){
System.out.println(getName()+" got lock. "+getState());
}else{
System.out.println(getName()+" could not get lock. "+getState());
}
}
}
}
public class TestClass
{
public static void main(String args[]) throws Exception
{
T t1 = new T("T1");
t1.start();
T t2 = new T("T2");
t2.start();
Thread.sleep(1000);
}
}


What is a possible output?

You had to select 1 option(s)

Q53. Consider the following code :

String id = c.readLine("%s", "Enter UserId:"); //1
System.out.println("userid is " + id); //2
String pwd = c.readPassword("%s", "Enter Password :"); //3
System.out.println("password is " + pwd); //4

Assuming that c is a valid reference to java.io.Console and that a user types jack as userid and jj123 as password, what will be the output on the console?

You had to select 1 option(s)

Q54. What is the result of executing the following code when the value of i is 5:

switch (i){
default:
case 1:
System.out.println(1);
case 0:
System.out.println(0);
case 2:
System.out.println(2);
break;
case 3:
System.out.println(3);
}

You had to select 1 option(s)

Q55. After which line will the object created at line XXX be eligible for garbage collection?

public Object getObject(Object a) //0
{

Object b = new Object(); //XXX

Object c, d = new Object(); //1
c = b; //2
b = a = null; //3
return c; //4
}

You had to select 1 option(s)