Infosys Certified L1 Junior Java Programmer

A constructor doesn't have any return type, because?

I) By default it returns the object on which class type it was created
II) Based on the type of the constructor called, returns any of the primitive types only
III) Nothing will be returned from a constructor either implicitly or explicitly.

Assuming all the necessary imports are done, predict the output of the below code:

public class FileStreamDemo {

public static void main(String[] args) throws Exception {
FileOutputStream fos = new FileOutputStream("sample.txt");
String text = "Java Basics";
byte[] b = text.getBytes();
fos.write(b);

FileInputStream fis = new FileInputStream("sample.txt");
int i = fis.read();
System.out.println((char)i);

fos.close();
fis.close();
}
}

Harry is implementing a generic class to store a collection of items and wants to ensure that the class can accept various types of objects. Which wildcard should be used in the generic class declaration to allow the class to accept any type of object?

Consider the following Java code:

// Assume all the necessary imports are done

public class StudentManager{
public static void main(String[] args) {
List<String> names = new ArrayList<>();
names.add("John");
names.add("Jane");
names.add("Alex");
names.add("Emily");

String searchTerm = "Alex";
boolean containsSearchTerm = names.contains(searchTerm);
int indexOfSearchTerm = names.indexOf(searchTerm);

System.out.println("Contains Search Term: "+containsSearchTerm);
System.out.println("Index of Search Term: "+indexOfSearchTerm);
}
}

What will be the output of the above code when executed?

You are working on a project that involves managing a list of employees. Each employee has a unique ID and a name. You want to create a generic class to handle this list.

The EmployeeList class is defined as follows:

public class EmployeeList<T>{
private List<T> employees;
public EmployeeList(){
employees=new ArrayList<>();
}
public void addEmployee(T employee){
employees.add(employee);
}
public T getEmployee(int id){
for(T employee : employees){
if(employee.getId()==id){
return employee;
}
}
return null;
}
}
Given the above code, which of the following statements is true?

What will be the output of the following code snippet? (Assume necessary class declaration is done and the main method is given)

StringBuffer sb = new StringBuffer("Welcome");
sb.replace(1, 3, "java");
System.out.println(sb);

Which of the following is the part of the output when the below code gets executed? (Choose exactly three correct options)

//Assume that code is written inside a main method with proper class declaration
var s = "Hello";
var t = new String(s);
if ("Hello".equals(s)) System.out.println("one");
if (t == s) System.out.println("two");
if (t.intern() == s) System.out.println("three");
if ("Hello" == s) System.out.println("four");
if ("Hello".intern() == t) System.out.println("five");

What code may be inserted at line 1 for successful compilation and execution of the below code?

Given:
import java.time.*;
import java.time.temporal.TemporalAdjusters;
public class Demo {

public static void main(String[] args) {
LocalDate today = LocalDate.now();
LocalDate lastDayOfYear = today.with(TemporalAdjusters.lastDayOfYear());
Period period = today.until(lastDayOfYear);
System.out.println();
System.out.println("Months remaining in the year: "+_______); // line 1
System.out.println();
}
}

What will be the output of the below code?
public class Demo {
public static void main(String[] args) {
int[] a = { 10, 20, 30};
int b = 0;
try { b = a[2];
System.out.println("Value of b=" + b);// Statement 1
String str = args[0];
System.out.println("Length of the string is:=" + str.length());//Statement 2
} catch (ArithmeticException|NullPointerException ec){
System.out.println("An exception has occurred");//Statement 3
} finally {
System.out.println("In the finally block");// Statement 4
}
System.out.println("Exception handled successfully");// Statement 5
} }

The InfyAccount team wants to find the average salary of employees using the below code.

Requirement:

• If the number of months <= 0, the code should display a message as "Invalid data".
• For validating the number of months, the developer has defined a custom-exception class 'MyException'.

Write a missing code for the MyException class to meet the above requirement.

//Missing Code for MyException class

public class Demo {

public static void printAverage(double totalSalary, int noOfMonths) throws MyException {
if (noOfMonths <= 0)
throw new MyException("Invalid data");
System.out.println("Average salary = Rs. " + totalSalary / noOfMonths);
}

public static void main(String[] args) {
try {
printAverage(400000, 12); // Output: Average salary = Rs. 33333.333333333336
//printAverage(400000, 0); // Output: Invalid data
} catch (MyException e) {
System.out.println(e.getMessage());
}
}

}
Choose the correct option from below.