Java Standard Test 7 – 2025

Q1. What will the following code print?

LocalDate ld = LocalDate.parse("2024-06-01");
LocalDateTime ldt1 = ld.atTime(LocalTime.of(10, 10));
LocalDateTime ldt2 = ldt1.plus(Period.ofDays(-1)).withHour(23);
if(ldt1.isAfter(ldt2) &! ldt1.getMonth().equals(ldt2.getMonth())){
System.out.println(ldt1.format(DateTimeFormatter.ofPattern("HHMM")));
}else{
System.out.println(ldt2.format(DateTimeFormatter.ofPattern("HHMM")));
}

Select 1 option(s):

Q2. What will be printed when the following code is compiled and run?

class A {
public int getCode(){ return 2;}
}

class AA extends A {
public long getCode(){ return 3;}
}

public class TestClass {

public static void main(String[] args) throws Exception {
A a = new A();
A aa = new AA();
System.out.println(a.getCode()+" "+aa.getCode());
}

public int getCode() {
return 1;
}
}

Select 1 option(s):

Q3. What will the following expression return?

"""
hello java \
guru
""".strip();

Select 1 option(s):

Q4. What will be the output of the following program?

class Data{
public volatile int d1 = 0;
public AtomicInteger d2 = new AtomicInteger(0);

}
public class TestClass
{

public static void main(String args[]) throws Exception
{
Data data = new Data();
Runnable r1 = () -> {
Thread t1 = Thread.currentThread();
for(;data.d1<2;){
System.out.print(t1.getName()+" : "+data.d1+" ");
data.d1++;
}
};

Runnable r2 = () -> {
Thread t1 = Thread.currentThread();
for(;data.d2.get()<2;){
System.out.print(t1.getName()+" : "+data.d2.get()+" ");
data.d2.getAndIncrement();
}
};

Thread t1 = new Thread(r1, "T1");
Thread t2 = new Thread(r2, "T2");
t1.start();
t2.start();

}
}

Select 1 option(s):

Q5. Given :

//In Data.java
public class Data{
int value;
Data(int value){
this.value = value;
}
public String toString(){ return ""+value; }
}

and the following code fragments:
public void filterData(ArrayList dataList, Predicate p){
Iterator i = dataList.iterator();
while(i.hasNext()){
if(p.test(i.next())){
i.remove();
}
}
}
....
ArrayList al = new ArrayList();
Data d = new Data(1); al.add(d);
d = new Data(2); al.add(d);
d = new Data(3); al.add(d);

//INSERT METHOD CALL HERE
System.out.println(al);

Which of the following options can be inserted above so that it will print [1, 3]?

Select 1 option(s):

Q6. Consider the following program:

public class TestClass extends Thread
{
private static int threadcounter = 0;
public void run()
{
threadcounter++;
System.out.println(threadcounter);
}
public static void main(String[] args) throws Exception
{
for(int i=0; i<10; i++)
{
synchronized(TestClass.class)
{
new TestClass().start();
}
}
}
}

Which of the following is correct regarding the execution of the given program?

Select 2 option(s):

Q7. What should be the return type of the following method?

public RETURNTYPE methodX( byte by){
var d = 10.0;
return (long) by/d*3;
}

Select 1 option(s):

Q8. What will be result of attempting to compile the following code appearing in TestClass.java file?

import java.util.*;
package test;
public class TestClass{
public OtherClass oc = new OtherClass();
}
class OtherClass{
int value;
}

Select 1 option(s):

Q9. What will the following code print when compiled and run?

class X{
public X(){
System.out.println("In X");
}
}

class Y extends X{
public Y(){
super();
System.out.println("In Y");
}
}

class Z extends Y{
public Z(){
System.out.println("In Z");
}
}

public class Test {

public static void main(String[] args) {
Y y = new Z();
}
}

Select 1 option(s):

Q10. Given:

class Person implements Serializable{
String name;
Person(String name){
this.name = name;
}
}

class Student extends Person{
String school;
public Student(String name, String school){
super(name);
this.school = school;

}
public String toString(){
return name+" "+school;
}
}
public class TestClass {
public static void main(String[] args) {
Person p = new Student("Bob Dylan", "NYU");
try(
ObjectOutputStream oos = new ObjectOutputStream(
new FileOutputStream("student.ser"));

ObjectInputStream ois = new ObjectInputStream(
new FileInputStream("student.ser"));
){
oos.writeObject(p);
oos.flush();
System.out.println((Student)ois.readObject());
}
}
}

What can be done so that the above code prints Bob Dylan NYU when run?

Select 1 option(s):

Q11. Given:

interface AmazingInterface{
String value = "amazing";
void amazingMethod(String arg);
}

abstract class AmazingClass implements AmazingInterface{
static String value = "awesome";
abstract void amazingMethod(String arg1, String arg2);
}


public class Awesome extends AmazingClass implements AmazingInterface {
public void amazingMethod(String arg1){ }
public void amazingMethod(String arg1, String arg2){ }

public static void main(String[] args){
AmazingInterface ai = new Awesome();

//INSERT CODE HERE
}

}

Identify the options that will cause compilation failure.

Select 3 option(s):

Q12. What will be the output of the following code:

SequencedCollection s1 = new ArrayList( );
s1.addFirst("a");
s1.addFirst("b");
s1.addLast("c");
s1.add("a");
System.out.println(s1.removeFirst()+" "+s1.remove("a")+" "+s1.remove("x"));

Select 1 option(s):

Q13. Given:

public class Book{
String isbn;
String title;
public Book(String isbn, String title){
this.isbn = isbn;
this.title = title;
}
public int compareTo(Book b){
return this.isbn.compareTo(b.isbn);
}
//accessors not shown
}

and the following code snippet:

List books = getBooksByAuthor("Ludlum");
Collections.sort(books, (b1, b2)->b1.getTitle().compareTo(b2.getTitle())); //1
Collections.sort(books); //2

Assuming that getBooksByAuthor is a valid method that returns a List of Books, which of the following statements is/are true?

Select 1 option(s):

Q14. Given:

sealed interface Building permits Hospital, Hotel{}

record Hospital(int beds) implements Building{};
record Hotel(int rooms) implements Building{};

public class TestClass {
static Building getBuilding(){
return Math.random()>.05?new Hotel(10): new Hospital(20);
}

public static void main(String[] args) {
Building b = getBuilding();
}
public static void printDetails(Building b){
if(b instanceof Hotel ht){
System.out.println("Hotel has "+ht.rooms()+" rooms");
}else if(b instanceof Hospital hp){
System.out.println("Hospital has "+hp.beds()+" beds");
}
else{
System.out.println("Building not recognized.");
}
}
}


Which of the following code snippets correctly implement the logic contained within the printDetails method?

Select 1 option(s):

Q15. Which statements about the following code are correct?

interface House{
public default String getAddress(){
return "101 Main Str";
}
}

interface Bungalow extends House{
public default String getAddress(){
return "101 Smart Str";
}
}

class MyHouse implements Bungalow, House{

}

public class TestClass {

public static void main(String[] args) {
House ci = new MyHouse(); //1
System.out.println(ci.getAddress()); //2
}
}

Select 1 option(s):

Q16. What will be written to the standard output when the following program is run?

Select 1 option(s):

Q17. Given:

char a = 'a', b = 98; //1
int a1 = a; //2
int b1 = (int) b; //3
System.out.println((char)a1+(char)b1); //4

What is the output?

Select 1 option(s):

Q18. What will be the output of the following lines ?

System.out.println("" +5 + 6); //1
System.out.println(5 + "" +6); // 2
System.out.println(5 + 6 +""); // 3
System.out.println(5 + 6); // 4

Select 1 option(s):

Q19. Which of the following are valid implementations of java.util.Comparator?

Select 3 option(s):

Q20.Given:

class MyProcessor{
public void process(){
System.out.println("Processing ");
}
}
public class TestClass {

public static void main(String[] args) {
process(()->new MyProcessor()); //1 REPLACE THIS LINE OF CODE
}

public static void process(Supplier s){
s.get().process();
}
}

Which of the following options correctly replaces the line marked //1 with code that uses method reference?

Select 1 option(s):

Q21. Consider the following class...

class Test{
public static void main(String[ ] args){
var a = new int[]{ 1, 2, 3, 4 };
int[] b = { 2, 3, 1, 0 };
System.out.println( a [ (a = b)[3] ] );
}
}

What will it print when compiled and run ?

Select 1 option(s):

Q22. What is the effect of compiling and running the code shown below?

public class TestClass{
public static void main (String args []){
var sum = 0;
for (int i = 0, j = 10; sum > 20; ++i, --j) // 1
{
sum = sum+ i + j;
}
System.out.println("Sum = " + sum);
}
}

Select 1 option(s):

Q23. Consider:

public class Outer
{
int i = 10;
class Inner
{
public void methodA()
{
//line 1.
}
}
}

Which of the following statements are valid at line 1?

Select 2 option(s):

Q24. A novice java programmer is unable to get a file named Coffee.java compiled. It contains the following enum definition:

public enum Coffee //1
{
ESPRESSO("Very Strong"), MOCHA, LATTE; //2
public String strength; //3
Coffee(String strength) //4
{
this.strength = strength; //5
}
public String toString(){ return strength + ordinal(); } //6
}

Which line is causing the problem?

Select 1 option(s):

Q25. You are trying to modularize an existing application that uses a few Apache open source jar files. Some of those jar files have been modularized but some have not. Details of such jar files are as follows:

commons-beanutils-1.9.jar

commons-collections4-4.0.jar
(Automatic-Module-Name: org.apache.commons.collections4)

commons-lang3-3.6.jar
(Automatic-Module-Name: org.apache.commons.lang3)

commons-text-1.2.jar
(Automatic-Module-Name: org.apache.commons.text)

What should the module-info file for your application contain?

Select 1 option(s):

Q26. Given:

String s1 = "Hello World";
String s2 = """
Hello World""";
System.out.println((s1 == s2)+" "+s1.equals(s2));

What is the result?

Select 1 option(s):

Q27. Given:

class A{
public List getList(){
//valid code
};
}
class B extends A{
@Override
*INSERT CODE HERE*
//valid code
};
}

What can be inserted in the above code?

Select 3 option(s):

Q28. Which of the lines will cause a compile time error in the following program?

public class MyClass{
public static void main(String args[]){
char c;
int i;
c = 'a';//1
i = c; //2
i++; //3
c = i; //4
c++; //5
}
}

Select 1 option(s):

Q29. Which of the following is/are a valid functional interface(s)?

Select 3 option(s):

Q30. What will be the contents of d at the end of the following code?

Deque d = new ArrayDeque();
d.add(1);
d.push(2);
d.pop();
d.offerFirst(3);
d.remove();
System.out.println(d);

Select 1 option(s):

Q31. Identify correct statement(s) about the following code:

public class FunWithOptional{
public static String getValue(){
return null;
}
public static void main(String[] args) {
Optional stro = Optional.of(getValue());//1
System.out.println(stro.isPresent());//2
System.out.println(stro.get());//3
System.out.println(stro.orElse(null));//4
}
}

Select 1 option(s):

Q32. Given that the file test.txt contains :

12345678
What will the following code print when compiled and run?

public static void main(String[] args) throws Exception{
try(var fis = new FileInputStream("c:\\temp\\test.txt");
var isr = new InputStreamReader(fis)){
while(isr.ready()){
isr.skip(1);
int i = isr.read();
char c = (char) i;
System.out.print(c);
}
}
}

Select 1 option(s):

Q33. Given the following contents of module-info.java,

module enthu.finance{
exports com.enthu.Reports;
requires enthu.utils;
}

Select correct statements.

Select 1 option(s):

Q34. Consider the following class :

class Test{
public static void main(String[] args){
for (var i = 0; i < 10; i++) System.out.print(i + " "); //1
for (var i = 10; i > 0; i--) System.out.print(i + " "); //2
var i = 20; //3
System.out.print(i + " "); //4
}
}

Which of the following statements are true?

Select 4 option(s):

Q35. Given the following method:

public static void copy(String fileName1, String fileName2) throws Exception{
try (
InputStream is = new FileInputStream(fileName1);
OutputStream os = new FileOutputStream(fileName2); ) {
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);
}
}
}

What will happen fileName1 contains only 100 bytes and fileName2 contains 200 bytes?

Select 1 option(s):

Q36. Given:

interface Instrument{
default void reset(){
System.out.println("In Instrument");
}
}

class Debt implements Instrument{
}

class Bond extends Debt{
public void reset(){
super.reset();
System.out.println("In Bond");
}
}

class ZCBond extends Bond{
ZCBond(){
reset();
}
public void reset(){
super.reset();
System.out.println("In ZCBond");
}

public static void main(String args[]){
Instrument i = new ZCBond();
}

}

What is the output?

Select 1 option(s):

Q37. Given the following code:

public class Valuator {
public AtomicInteger status = new AtomicInteger(0);
public void valuate() {
int oldstatus = status.get();
/* valid code here */
int newstatus = //determine new status

//INSERT CODE HERE

}
}
Assuming that an instance of this class is shared among multiple threads, you want to update the status to newstatus only if the oldstatus has not changed. Which of the following lines of code will you use?

Select 1 option(s):

Q38. Assume that the following directory exists:

c:\a\b\c

A File object is created as follows:

var f = new File("c:\\a\\b\\c\\d\\e");

Given that directories d and e do not exist under c, which of the following statements are correct?

Select 2 option(s):

Q39. Consider the following class :

public class Parser{
public static void main( String[] args){
try{
int i = 0;
i = Integer.parseInt( args[0] );
}
catch(NumberFormatException e){
System.out.println("Problem in " + i );
}
}
}

What will happen if it is run with the following command line:
java Parser 1_00

Select 1 option(s):

Q40. What will the following code print when run?

import java.nio.file.Path;
import java.nio.file.Paths;

public class PathTest {
static Path p1 = Paths.get("c:\\main\\project\\Starter.java");

public static String getRoot(){
String root = p1.getRoot().toString();
return root;
}

public static void main(String[] args) {
System.out.println(getRoot());
}
}

Select 1 option(s):

Q41. Which of the following declarations are valid?

Select 4 option(s):

Q42. Given:

class Base{
public Collection transform(Collection list)
{
return new ArrayList();
}
}

class Derived extends Base{
/* public Collection transform(Collection list) {
return new HashSet();
}; */ //1

/* public Collection transform(Stream list) {
return new HashSet();
}; */ //2

/* public List transform(Collection list) {
return new ArrayList();
}; */ //3

/*public Collection transform(Collection list) {
return new HashSet();
}; */ //4

/* public Collection transform(Collection list) {
return new HashSet();
}; */ //5

}

Identify correct statements about the methods defined in Derived assuming they are uncommented one at a time individually.

Select 2 option(s):

Q43. Consider the following class:

class TestClass{
void probe(int... x) { System.out.println("In ..."); } //1

void probe(Integer x) { System.out.println("In Integer"); } //2

void probe(long x) { System.out.println("In long"); } //3

void probe(Long x) { System.out.println("In LONG"); } //4

public static void main(String[] args){
Integer a = 4; new TestClass().probe(a); //5
int b = 4; new TestClass().probe(b); //6
}
}

What will it print when compiled and run?

Select 2 option(s):

Q44. Which of the options will create and initialize a matrix of ints as shown below?

	1
	1
	1
	1
	1

Select 1 option(s):

Q45. What will the following code print when compiled and run?

Select 1 option(s):

Q46. What will the following code print?

int i = 0;
int j = 1;
if( (i++ == 0) & (j++ == 2) ){
i = 12;
}
System.out.println(i+" "+j);

Select 1 option(s):

Q47. Identify the correct statement(s).

Select 2 option(s):

Q48. Given:

public class Buddy {
Buddy upper;
String name;
public Buddy(){ }

public Buddy(String name){
this.name = name;
}
public Buddy(String name, Buddy upper){
this.name = name;
Buddy b = new Buddy(upper.name);//1
upper = b; //2
}

public static void main(String[] args) {
Buddy b1 = new Buddy("A"); //3
Buddy b2 = new Buddy("B", b1); //4
System.out.println(b1); //5
}
}

Identify correct statements.

Select 2 option(s):

Q49. Which of the given options if put at //1 will correctly instantiate objects of various classes defined in the following code?

public class TestClass
{
public class A{
}
public static class B {
}
public static void main(String args[]){
class C{
}
//1
}
}

Select 2 option(s):

Q50. What will the following code print when compiled and run?

var numA = new Integer[]{1, 2};
var list1 = new ArrayList(List.of(numA));
list1.add(null);
var list2 = Collections.unmodifiableList(list1);
list1.set(2, 3);
List<List> list3 = List.of(list1, list2);
System.out.println(list3);

Select 1 option(s):