Java Intermediate Certification Practice Test: 55 Expert Questions

Q1. Given:

module abc.blogger {
requires serviceapi;
provides api.BloggerService with abc.SimpleBlogger;
}

Which of the following code fragments appearing in another module correctly loads a service provider that implements api.BloggerService?

You had to select 1 option(s)

Q2. What will the following code print?

int[] ia1 = { 0, 1, 4, 5};
int[] ia2 = { 0, 1, 1, 5, 6};

int x = Arrays.compare(ia1, ia2);
int y = Arrays.mismatch(ia1, ia2);
System.out.println(x+" "+y);

You had to select 1 option(s)

Q3. What will be the contents of s1 and s2 when the control reaches the println statement in the main method of the following program?

import java.util.*;
public class TestClass{
public static void main(String args[]){
Stack s1 = new Stack ();
Stack s2 = new Stack ();
processStacks (s1, s2);
System.out.println (s1 + " "+ s2);
}
public static void processStacks(Stack x1, Stack x2){
x1.push (Integer.valueOf("100"));
//assume that the method push adds the passed object to the stack.
x2 = x1;
}
}

Note:[] is used in the options below to denote each element of the Stack.

You had to select 1 option(s)

Q4. What will the following program print?

class Test{
public static void main(String[] args){
var i = 4;
int ia[][][] = new int[i][i = 3][i];
System.out.println( ia.length + ", " + ia[0].length+", "+ ia[0][0].length);
}
}

You had to select 1 option(s)

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

int [] [] array = {{0}, {0, 1}, {0, 1, 2}, {0, 1, 2, 3}, {0, 1, 2, 3, 4}};
var arr1 = array[4];
System.out.println (arr1[4][1]);
System.out.println (array[4][1]);

You had to select 1 option(s)

Q6. Given:

public class Book{
private String title;
private Double price;
public Book(String title, Double price){
this.title = title;
this.price = price;
}
//accessor methods not shown
}

What will the following code print when compiled and run?

Book b1 = new Book("Java in 24 hrs", 30.0);
Book b2 = new Book("Thinking in Java", null);
Supplier s1 = b1::getPrice;
System.out.println(b1.getTitle()+" "+s1.get());
Supplier s2 = b2::getPrice;
System.out.println(b2.getTitle()+" "+s2.getAsDouble());

You had to select 1 option(s)

Q7. Identify the correct statements about the following code fragment:

var fw = new FileWriter("c:\\temp\\test.txt");
var bfw = new BufferedWriter(fw);
bfw.writeUTF("hello"); //1
bfw.newLine(); //2
bfw.write("world"); //3

You had to select 1 option(s)

Q8. Assuming that the directory /works/ocpjp/code exists but /works/ocpjp/code/sample does not exist, what will the following code output?

Path d1 = Paths.get("/works");
Path d2 = d1.resolve("ocpjp/code"); //1
d1.resolve("ocpjp/code/sample"); //2
d1.toAbsolutePath(); //3
System.out.println(d1);
System.out.println(d2);

You had to select 1 option(s)

Q9. Identify the correct statements about Java Stream API.

You had to select 1 option(s)

Q10. Given:

public class Movie{
private String title;
private String genre;
public Movie(String title, String genre){
this.title = title;
this.genre = genre;
}
//accessors not shown
}

and

Stream sm = Stream.of( new Movie("a1", "a"),
new Movie("a2", "a"),
new Movie("b1", "b"), new Movie("c1", null));


Which of the following code fragments will get the number of movies that do not belong to any genre (i.e. where genre is null)?

You had to select 1 option(s)

Q11. Given:

class Booby{
}
class Dooby extends Booby{
}
class Tooby extends Dooby{
}

and the following declarations:

List bV = null;
List tV = null;

Which of the following statements will compile without any error?

You had to select 1 option(s)

Q12. You want to execute a task that returns a result without blocking. Which of the following types from java.util.concurrent package will be required to achieve this?

You had to select 4 option(s)

Q13. Identify the valid for loop constructs assuming the following declarations:

Object o = null;
Collection c = //valid collection object.
int[][] ia = //valid array

You had to select 2 option(s)

Q14. What will the following code print?

List names = Arrays.asList(1, 2, 3); //1
names.forEach(x->x=x+1); //2
names.forEach(System.out::println); //3

You had to select 1 option(s)

Q15. What can be inserted in the following code so that it will print [21, 32, 43] ?

List ls = Arrays.asList(11, 22, 33);
//INSERT CODE HERE
ls.replaceAll(func);
System.out.println(ls);

You had to select 1 option(s)

Q16. Which line in the following code will cause the compilation to fail?

public class TestClass {

public static void main(String[] args) throws Exception {
work(); //LINE 10
int j = j1; //LINE 11
int j1 = (double) x; //LINE 12
}

public static void work() throws Exception{
System.out.println(x); //LINE 15
}

static double x; //19
}

You had to select 2 option(s)

Q17. What happens when you try to compile and run the following program?

public class CastTest{
public static void main(String args[ ] ){
byte b = -128 ;
int i = b ;
b = (byte) i;
System.out.println(i+" "+b);
}
}

You had to select 1 option(s)

Q18. 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?

You had to select 1 option(s)

Q19. Consider the following code :

import java.util.*;
class Request { }
class RequestCollector{
//1 : Insert declaration here

public synchronized void addRequest(Request r){
container.add(r);
}
public synchronized Request getRequestToProcess(){
return container.poll();
}
}

What can be inserted at //1?

You had to select 1 option(s)

Q20. What will be the result of attempting to compile and run the following code?

public class InitClass{
public static void main(String args[ ] ){
InitClass obj = new InitClass(5);
}
int m;
static int i1 = 5;
static int i2 ;
int j = 100;
int x;
public InitClass(int m){
System.out.println(i1 + " " + i2 + " " + x + " " + j + " " + m);
}
{ j = 30; i2 = 40; } // Instance Initializer
static { i1++; } // Static Initializer
}

You had to select 1 option(s)

Q21. You want to invoke the overridden method (the method in the base class) from the overriding method (the method in the derived class) named m().

Which of the following constructs which will let you do that?

You had to select 1 option(s)

Q22. You want to change the default locale for formatting numbers, currency, and percentages. Which of the following statements will achieve that?

You had to select 2 option(s)

Q23. Given:

byte b = 1;
char c = 1;
short s = 1;
int i = 1;

which of the following expressions are valid?

You had to select 3 option(s)

Q24. Given that classes B1 and B2 extend class A and classes C1, C2 are subclasses of B1.

Further, assume that method public void m1(){ ... } is defined in all of these classes EXCEPT B1 and C1.

class A{
public void m1(){ }
}

class B1 extends A{
}
class B2 extends A{
public void m1(){ }
}

class C1 extends B1{
}
class C2 extends B1{
public void m1(){ }
}


Assume that "objectOfXX" means a variable that points to an object of class XX. So, objectOfC1 means a reference variable that is pointing to an object of class C1.

Which of the following statements are correct?

You had to select 1 option(s)

Q25. What will the following program print?

public class TestClass{
public static void main(String[] args){
var str = "111";
boolean[] bA = new boolean[1];
if( bA[0] ) str = "222";
System.out.println(str);
}
}

You had to select 1 option(s)

Q26. Which of the following method definitions will prevent overriding of that method?

You had to select 4 option(s)

Q27. Given:

enum Coffee
{
ESPRESSO("Very Strong"), MOCHA("Bold"), LATTE("Mild");
public String strength;
Coffee(String strength)
{
this.strength = strength;
}
}

and the statement
System.out.println(Coffee.ESPRESSO);

What can be done so that the above statement will print Very Strong?

You had to select 1 option(s)

Q28. What can be inserted in the following code at //1 so that it will print the number of lines present in the given file?

public void countLines(String filePath) throws Exception{
//1
System.out.println(ref.count());
}

You had to select 2 option(s)

Q29. Assuming that the following code compiles without any error, identify correct statements.

interface Processor {
A process(String str);
}

class ItemProcessor implements Processor{
@Override
public B process(String str){
return new B(str);
}
}

You had to select 2 option(s)

Q30. Identify the correct statements about ArrayList?

You had to select 3 option(s)

Q31. Which of the following statements are true?

You had to select 1 option(s)

Q32. What will the following code print?

int x = 1;
int y = 2;
int z = x++;
int a = --y;
int b = z--;
b += ++z;

int answ = x>a?y>b?y:b:x>z?x:z;
System.out.println(answ);

You had to select 1 option(s)

Q33. What is the result of executing the following fragment of code:

boolean b1 = false;
boolean b2 = false;
if (b2 != b1 = !b2){
System.out.println("true");
}
else{
System.out.println("false");
}

You had to select 1 option(s)

Q34. Given the following code:

import java.util.Arrays;
import java.util.List;
public class TestClass {
public static void main(String[] args) {
List al = Arrays.asList(100, 200, 230, 291, 43);

System.out.println( *INSERT CODE HERE* );
}
}

Which of the following options will correctly print the number of elements that are less than 200?

You had to select 1 option(s)

Q35. What will the following code NEVER print when run?

enum SIZE
{
TALL, JUMBO, GRANDE;
}

class CoffeeMug
{

public static void main(String[] args)
{
var hs = new HashSet();
hs.add(SIZE.TALL); hs.add(SIZE.JUMBO); hs.add(SIZE.GRANDE);
hs.add(SIZE.TALL); hs.add(SIZE.TALL); hs.add(SIZE.JUMBO);
for(SIZE s : hs) System.out.print(s+" ");
}
}

You had to select 2 option(s)

Q36. Given:

class MyGenericClass{
public String transform(T t){
return t.toString()+"-"+t.hashCode();
}
}

and the following code snippet:

MyGenericClass gc = new MyGenericClass();
System.out.println(gc.transform(1)); //1
System.out.println(gc.transform("hello")); //2
MyGenericClass gcStr = new MyGenericClass();
System.out.println(gcStr.transform(1.1)); //3


What will it print when compiled and run?

You had to select 1 option(s)

Q37. Given the follow two module definitions:

module author{
requires serviceapi;
uses api.BloggerService;
}

and

module abc.blogger{
requires serviceapi;
provides api.BloggerService with abc.SimpleBlogger;
}


Identify correct statement(s).

You had to select 2 option(s)

Q38. Consider the following code:

Instant ins = Instant.now();
System.out.println(ins);


Given that the local time where the code is run is 3PM and the local time zone is 2 hours ahead of UTC, what will the above code print?
(Assume that the date is 20th Jan 2022).

You had to select 1 option(s)

Q39. Given the following code:

import java.util.Arrays;
import java.util.List;
public class TestClass {
public static void main(String[] args) {
List al = Arrays.asList("aa", "aaa", "b", "cc", "ccc", "ddd", "a");
//INSERT CODE HERE
System.out.println(count);
}
}

Which of the following options will correctly print the number of elements that will come before the string "c" if the list were sorted alphabetically?

You had to select 1 option(s)

Q40. Consider the following code:

import java.util.*;
class Book{ }
class TextBook extends Book{ }

class BookList extends ArrayList
{
public int count = 0;
public boolean add(Object o)
{
if(o instanceof Book b) return super.add(b);
else return count++ == -1;
}
}

//in valid context
BookList list = new BookList();
list.add(new Book());
list.add(new TextBook());
list.add("hello");

System.out.println(list.count);

What will it print?

You had to select 1 option(s)

Q41. What will be the result of attempting to compile and run the following class?

public class TestClass{
public static void main(String args[ ] ){
int i, j, k;
i = j = k = 9;
System.out.println(i);
}
}

You had to select 2 option(s)

Q42. Given:

Connection con = DriverManager.getConnection(dbURL);
String updateString =
"update SALES " +
"set T_AMOUNT = 100 where T_NAME = 'BOB'";
Statement stmt = con.createStatement();
stmt.executeUpdate(updateString);
//INSERT CODE HERE

What statement should be added to the above code so that the update is committed to the database?

You had to select 1 option(s)

Q43. Identify correct statements about -classpath and --module-path options while executing a java program.

You had to select 3 option(s)

Q44. Which statements about the following code contained in BankAccount.java are correct?

interface Account{
public default String getId(){
return "0000";
}
}

interface PremiumAccount extends Account{
public String getId();
}

public class BankAccount implements PremiumAccount{
public static void main(String[] args) {
Account acct = new BankAccount();
System.out.println(acct.getId());
}

}

You had to select 1 option(s)

Q45. Which of the following interface definitions can use Lambda expressions?

You had to select 1 option(s)

Q46. Given:

class Booby{
}
class Dooby extends Booby{
}
class Tooby extends Dooby{
}

public class TestClass {
Booby b = new Booby();
Tooby t = new Tooby();
public void do1(List dataList){
//1 INSERT CODE HERE
}
public void do2(List dataList){
//2 INSERT CODE HERE
}
}
and the following four statements:

1. b = dataList.get(0);
2. t = dataList.get(0);
3. dataList.add(b);
4. dataList.add(t);

What can be inserted in the above code?

You had to select 1 option(s)

Q47. What will the following line of code print?

System.out.println(LocalDate.of(2022, Month.JANUARY, 01)
.format(DateTimeFormatter.ISO_DATE_TIME));

You had to select 1 option(s)

Q48. What will the following program print?

public class TestClass{
static boolean b;
static int[] ia = new int[1];
static char ch;
static boolean[] ba = new boolean[1];
public static void main(String args[]) throws Exception{
var x = false;
if( b ){
x = ( ch == ia[ch]);
}
else x = ( ba[ch] = b );
System.out.println(x+" "+ba[ch]);
}
}

You had to select 1 option(s)

Q49. What, if anything, is wrong with the following code?

void test(int x){
switch(x){
case 1:
case 2:
case 0:
default :
case 4:
case 'a'|'b': System.out.println('c');
}
}

You had to select 1 option(s)

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

public class Discounter {
static double percent; //1
int offset = 10, base= 50; //2
public static double calc(double value) {
var coupon, offset, base; //3
if(percent <10){ //4
coupon = 15;
offset = 20;
base = 10;
}
return coupon*offset*base*value/100; //5
}
public static void main(String[] args) {
System.out.println(calc(100));
}
}

You had to select 1 option(s)

Q51. 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 "xxx-xxx-"+dddd, where dddd represents the same four digits in the original number?

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

You had to select 2 option(s)

Q52. Given:

var al = new ArrayList();
al.forEach( k -> {
System.out.print(k.length());
});


Identify correct statements.

You had to select 1 option(s)

Q53. Given:

//in file Movable.java
package p1;
public interface Movable {
int location = 0;
void move(int by);
public void moveBack(int by);
}


//in file Donkey.java
package p2;
import p1.Movable;
public class Donkey implements Movable{
int location = 200;
public void move(int by) {
location = location+by;
}
public void moveBack(int by) {
location = location-by;
}
}


//in file TestClass.java
package px;
import p1.Movable;
import p2.Donkey;
public class TestClass {
public static void main(String[] args) {
Movable m = new Donkey();
m.move(10);
m.moveBack(20);
System.out.println(m.location);
}
}

Identify the correct statement(s).

You had to select 1 option(s)

Q54. Identify correct statements about the modular JDK.

You had to select 3 option(s)

Q55. Which of these statements concerning maps are true?

You had to select 1 option(s)