LinkedIn Java Skill Assessment Answers 2021

Q1. What is the output of this code?

class Main {    public static void main (String[] args) {        String message = “Hello world!”;        String newMessage = message.substring(6, 12)            + message.substring(12, 6);        System.out.println(newMessage);    }}

• The code does not compile.
• A runtime exception is thrown <<<<—Correct
• “world!!world”
• “world!world!”
• String m = “Hello world!”;
• String n = m.substring(6,12) + m.substring(12,6);
• System.out.println(n);

Q2. How do you write a foreach loop that will iterate over ArrayList<Pencil>pencilCase?

• for(Pencil pencil = pencilCase){}
• Iterator iterator = pencilCase.iterator();
• for(){iterator.hasNext()}{}

Q3. Fill in the blanks?

Object-oriented programming (OOP) is a programming language model that organizes software design around (objects), rather than (actions).

Q4. What code would you use to tell if “schwifty” is of type String?

• “schwifty”.getType() == String
• “schwifty”.getClass().getsimpleName() == “String”
• “schwifty”.getType().equals(“String”)
• “schwifty” instanceof String <<<<—Correct

Q5. Correct output of “apple”.compareTo(“banana”)

• 0
• positive number
• negative number <<<<—Correct
• compilation error

Q6. You have an ArrayList of names that you want to sort alphabetically. Which approach would NOT work?

• names.sort(Comparator.comparing(String::toString))
• Collections.sort(names)
• names.sort(List.DESCENDING) <<<— Correct (not too sure)
• names.stream().sorted((s1, s2) -> s1.compareTo(s2)).collect(Collectors.toList())

Q7. By implementing encapsulation, you cannot directly access the class’s _____ properties unless you are writing code inside the class itself.

• private <<<<—Correct
• protected
• no-modifier
• public

Q8. Which is the most up-to-date way to instantiate the current date?

• new SimpleDateFormat(“yyyy-MM-dd”).format(new Date())
• new Date(System.currentTimeMillis())
• LocalDate.now()
• Calender.getInstance().getTime() <<<<— Correct

Q9. Fill in the blank to create a piece of code that will tell wether int0 is divisible by 5:

• boolean isDivisibleBy5 = _____
• int0 / 5 ? true: false
• int0 % 5 == 0 <<<<—Correct
• int0 % 5 != 5
• Math.isDivisible(int0, 5)

Q10. How many time will this code print “Hello World!”?
Class Main {
public static void main(String[] args){
for (int i=0; i<10; i=i++){
i+=1;
System.out.println(“Hello World!”);
}
}
}

• 10 times
• 9 times
• 5 times <<<<—Correct
• infinite number of times

Q11. The runtime system starts your program by calling which function first?

• print
• iterative
• hello
• main <<<<—Correct

Q12. What is the result of this code?
try{
System.out.print(“Hello World”);
}catch(Exception e){
System.out.println(“e”);
}catch(ArithmeticException e){
System.out.println(“e”);
}finally{
System.out.println(“!”);
}

• It will throw a runtime exception
• It will not compile <<<<—Correct
• Hello World!
• Hello World

Q13. Which statement is NOT true?

• An anonymous class may specify an abstract base class as its base type.
• An anonymous class does not require a zero-argument constructor. <<<<—Correct
• An anonymous class may specify an interface as its base type.
• An anonymous class may specify both an abstract class and interface as base types

Q14. What will this program print out to the console when executed?
public class Main {   
public static void main(String[] args){
       LinkedList<Integer> list = new LinkedList<>();
       list.add(5);
       list.add(1);
       list.add(10);
       System.out.println(list);
    }
}

• [5, 1, 10] <<<<—Correct
• [10, 5, 1]
• [1, 5, 10]
• [10, 1, 5]

Q15. What is the output of this code?
class Main {   
public static void main(String[] args){
        String message = “Hello”;       
for (int i = 0; i<message.length(); i++){
System.out.print(message.charAt(i+1));       
}   
}
}    

• “Hello”
• A runtime exception is thrown. <<<<—Correct
• The code does not compile.
• “ello”

Q16. Object-oriented programming is a style of programming where you organize your program around ____ rather than ____ and data rather than logic.

•  functions; actions
•  objects; actions
•  actions; functions
•  actions; objects

Q17. Given the string “strawberries” saved in a variable called fruit, what would “fruit.substring(2, 5)” return?

• rawb
• raw <<<<—Correct
• awb
• traw

Q18. How can you achieve runtime polymorphism in Java?

• method overloading
• method overrunning
• method overriding <<<<— Correct
• method calling

Q19. Given the following definitions, which of these expressions will NOT evaluate to true?
boolean b1 = true, b2 = false;
int i1 = 1, i2 = 2;

• (i1 | i2) == 3
• i2 && b1 <<<<—Correct
• b1 || !b2
• (i1 ^ i2) < 4

Q20. What can you use to create new instances in Java?

• constructor <<<<—Correct
• another instance
• field
• private method

Q21. What is the output of this code?
class Main {
public static void main (String[] args) {
int array[] = {1, 2, 3, 4};
for (int i = 0; i < array.size(); i++) {
System.out.print(array[i]);
}
}
}

• It will not compile because of line 4. <<<<—Correct
• It will not compile because of line 3.
• 123
• 1234

Q22. Which of the following can replace the CODE SNIPPET to make the code below print “Hello World”?
interface Interface2 {
static void print() {
System.out.print(“World!”);
}
}

• super1.print(); super2.print();
• this.print();
• super.print();
• Interface1.print(); Interface2.print();

Q23. What does the following code print?String str = “”abcde””;str.trim();str.toUpperCase();str.substring(3, 4);System.out.println(str);

• CD
• CDE
• D
• “abcde” <<<<—Correct

Q24. What is the result of this code?
class Main {
   public static void main (String[] args){
     System.out.println(print(1));
   }
   static Exception print(int i){
       if (i>0) {
          return new Exception();
       }
else {
          throw new RuntimeException();
      }
  }
}

• It will show a stack trace with a runtime exception.
• “java.lang.Exception” <<<<—Correct
• It will run and throw an exception.
• It will not compile.

Q25. Which class can compile given these declarations?
interface One {
default void method() {
System.out.println(“”One””);
}   }
interface Two {
default void method () {
System.out.println(“”One””);
}
} 

•  class Three implements One, Two {

publc void method() {        super.One.method();  } }

•   class Three implements One, Two {

publc void method() {        One.method();  } }

• class Three implements One, Two {

}

•   class Three implements One, Two { <—— correct

    publc void method() {        One.super.method();  } }

Q26. What is the output of this code?
class Main {
public static void main (String[] args) {
List list = new ArrayList();
list.add(“hello”);
list.add(2);
System.out.print(list.get(0) instanceof Object);
System.out.print(list.get(1) instanceof Integer);
}
}

• The code does not compile.
• truefalse
• truetrue <<<<—Correct
• falsetrue

Q27. Given the following two classes, what will be the output of the Main class?
package mypackage;
public class Math {
    public static int abs(int num){
        return num<0?-num:num;
    }
}
package mypackage.elementary;
public class Math {
    public static int abs (int num) {
        return -num;
    }
}
import mypackage.Math;
import mypackage.elementary.*;
class Main {
  public static void main (String args[]){
    System.out.println(Math.abs(123));
  }
}

• Lines 1 and 2 generate compiler erros due to class name conflicts.
• “-123”
• It will throw an exception on line 5.
• “123” <— Correct // The answer is “123”. The abs() method evaluates to the one inside mypackage.Math class.

Q28. What is the result of this code?
class MainClass {
final String message(){
return “Hello!”;
}
}
class Main extends MainClass {
public static void main(String[] args) {
System.out.println(message());
}
String message(){
return “World!”;
}
}

• It will not compile because of line 10. <— Correct
• “Hello!”
• It will not compile because of line 2.
• “World!”

Q29. Given this code, which command will output “2”?
class Main {
    public static void main(String[] args) {
        System.out.println(args[2]);
    }
}

• java Main 1 2 “3 4” 5
• java Main 1 “2” “2” 5 <— Correct
• java Main.class 1 “2” 2 5
• java Main 1 “2” “3 4” 5

Q30. What is the output of this code?
class Main {    public static void main(String[] args){        int a = 123451234512345;        System.out.println(a);    }}

• “123451234512345”
• Nothing – this will not compile. <<<<—Correct
• a negative integer value
• “12345100000”

Q31. What is displayed when this code is compiled and executed?
Public class main {
public static void main(string[] args) {
int x= 5;x = 10;System.out.println(x);
  }
}

• 5
• null
• x
• 10 – Correct answers

Q32. What statement returns true if “nifty” is of type String?

• “nifty”.getType().equals(“string”)
• “nifty”.getClass().getSimpleName() == “String”
• “nifty” instantceof String – Correct Answer
• “nifty” .getType() == String

Q33. Given the string “strawberries” saved in a variable called fruit, what would fruit .substring(2, 5) return?

• raw – Correct Answer
• rawb
• traw
• awb

Q34. What is the result of this code?
try{  System.out.print(“Hello World”);}catch(Exception e) {  System.out.println(“e”);}catch(ArithmeticException e) { System.out.println(“e”);}finalyy{ System.out.println(“!”);}

• It will not compile because the second catch statement is unreachable. – Correct Answer
• Hello World
• Hellow World!
• It will thwow a runtime exception.

Q35. How many times will this code print “Hello World”?
class Main{ public static void main(String[] args) {
for (int i=0; i<10; i=i++){    i+=1;    System.out.println(“Hello World!”);   }  }}

• 9 times
• infinite number of times
• 5 times
• 10 times – Correct Answer

Q36. What is the result of this code?
class Main { Object message(){ return “Hello!”;
} public static void main(String[] args) { System.out.print(new main().MESSAGE()); System.out.print(new Main2().message()); }}class Main2 extends Main { String message(){ return “World!”;  }}

• It will compile because of line 7.
• Hello!Hello!
• Hello!World! – Correct Answers
• It will not compile because of line 11.

Q37. You have an ArrayList of names that you want to sort alphabetically. Which approach would not work?

• names.sort(Comparator.comparing(String::toString))
• names = names.stream().sorted((s1, s2) ->

s1.compareTo(s2)).collect(Collectors.toList())

• names.sort(List.DECENDING) – Correct Answer
• Collections.sort(names)

Q38. What is the output of this code?
import java.util.*;class Main {  public static void main(String[] args) {  List<Boolean> list = new ArrayList<>();  list.add(true);  list.add(Boolean.parseBoolean(“False”));  list.add(Boolean.TRUE);  System.out.print(list.size());  System.out.print(list.get(1) instanceof Boolean);  }}

• 3false
• 3true
• 2true
• A runtime exception is thrown -Correct Answer

Q39. What method can be used to create a new instance of an object?

• another instance
• field
• private method
• constructor – Correct Answer

Q40. How can you achieve runtime polymorphism in Java?

• method calling
• method overrunning
• method overriding
• method overloading – Correct Answer

Q41. What is the output of this code?
class Main { public static void main(String[] args) { String message = “Hello wold!”; String newMessage = message.substring(6, 12) + message.substring(12, 6); System.out.println(newMessage); }}

• The code does not compile
• A runtime exception is thrown. – Correct Answer
• world!world!
• world!!world

Q42. Which is the most reliable expression for testing whether the values of two string variables are the same?

• string1 == string2
• string1.equals(string2) – Correct Answer
• string1 = string2
• string1.matches(string2)

Q43. What is the output of this code?
class Main {
static int cound = 0;
public static void main(String[] args)  {
if(cound <3)
{count++;main(null);}
else{  return;
}   System.out.println(“Hello World”);
}
}

• it will throw a runtime exception.
• it will print “Hello World!” three times.
• it will not compile.
• it will run forever. – Correct Answer

Q44. What is the output of this code?
class main {
  public static void main(String[] args) {
   List list = new ArrayList();   list.add(“hello”);
   list.add(2);
   System.out.print(list.get(0) instanceof Object);   System.out.print(list.get(1) instanceof Integer);
  }
}

• falsetrue
• The code does not compile.
• truetrue – Correct Answer
• truefalse

Q45. By implementing encapsulation, you cannot directly access the class’s_____properties unless you are writing code inside the class itself.

• private – Correct Answer
• protected
• public
• no-modifier

Java is an object-oriented programming language with a high level of abstraction and as few implementation dependencies as possible. It is a general-purpose programming language that allows application developers to write once and run anywhere (WORA), which means that compiled Java code can operate on any platform that supports Java without the need to recompile. Java applications are usually compiled to bytecode, which may execute on any Java virtual machine (JVM), regardless of the computer architecture.