HCL Interview Questions

HCL interview Questions

HCL (Hindustan Computers Limited) Technologies is an Information Technology (IT) Services and consulting company. It’s headquartered in Noida, India and operates in 45 countries. HCL Technologies is a prominent company that assists enterprises in transforming their operations to align with the digital era. They provide strategic guidance on Digital, Automation, Analytics, Cloud, IoT, Cybersecurity, Infrastructure Management, and Engineering Services.

HCL interview Questions

HCL Technologies operates across a diverse range of sectors, from banking and automotive to healthcare, as well as media and entertainment. This company ranks among the top 20 publicly traded companies in India and is listed in the Forbes Global 2000. If you prioritize innovation and a strong organizational culture, HCL could be the ideal workplace for you. HCL places significant emphasis on the personal and professional growth of its employees, fostering a people-centric culture that has made a considerable impact on society.

They embrace the concept of ‘Ideapreneurship,’ where employees lead in driving innovation by nurturing their ideas. This culture of innovation and collaboration has led to the development of numerous pivotal factors that drive business success. It not only encourages pushing boundaries but also enables personal growth and the expansion of horizons. HCL Technologies is globally recognized as one of the most influential companies, and they are dedicated to inspiring, empowering, and supporting their employees throughout the organization. We will discuss the frequently asked HCL interview questions for Freshers jobs seekers.

If you are searching for new job postings, visit Freshers Jobs in Bangalore.

Interview Process

HCL (Hindustan Computers Limited) consistently engages in recruitment activities, conducting annual hiring initiatives to onboard new and skilled individuals for various job positions. Typically, the company’s selection procedure consists of these four stages.

  • Written/Aptitude Assessment Round
  • Group Discussion
  • Technical Interview Round
  • HR Round

Interview Rounds

  • Written/Aptitude Assessment Round: The round in the HCL recruitment process is the Written or Aptitude Assessment Round. Questions asked in this round will be about quantitative ability and verbal reasoning. These questions will be in the form of multiple-choice questions in general and will be conducted online.
  • Group Discussion: The second round in the interview process is Group discussion. This round is an essential part of the selection process. The recruiters will assess specific personality traits of candidates to determine whether they are culturally fit. In this round, a common topic will be given, and the candidates should share their ideas or perspectives related to it. The topics can also be given regarding recent events. Personality traits assessed in this round are Team spirit, an ability to answer spontaneously, conflict resolving/ problem solving, insights into the given topic, etc.
  • Technical Interview Round: The third round in the HCL recruitment process is the Technical Interview Round. Questions asked in this round will be about C, C++, Java, UNIX, LINUX, etc. It is necessary to be well-prepared with the fundamental concepts of all these topics to crack this round. There are a lot of possibilities for the interviewers to ask questions regarding your projects, so ensure that you are well-prepared for it.
  • HR Round: The final round of this selection process is the HR round. Generally, questions asked in this round will be about general topics. They might also assess a candidate’s interest in working in a specific company. They would also ask about your personal and career goals, passion, why you want to work in this company, etc.

You can find new job openings in HCL Jobs for freshers.

HCL Technical Interview Questions

Given below are the frequently asked HCL technical interview questions.

  1. Define input-output (I/O) in C++.

Input-output (I/O) in C++ involves the use of streams for handling data. In C++, the input stream is employed to receive input from sources like the console (i.e., user input), while the output stream is used to showcase the results of operations on the console or an output device. The standard input-output stream in C++ is represented by “iostream,” and it encompasses various methods such as “cin” and “cout.”

  1. Write the difference between structured English and Pseudo Code.

Structured English is employed for outlining the structure of a program module and is based on the English language, incorporating programming language keywords. In contrast, Pseudo Code resembles a programming language but lacks the syntax of any particular programming language.

  1. What is the purpose of the Domain Name System (DNS)?

The primary purpose of the DNS (Domain Name System) is the translation of the domain’s names into IP Addresses. Computers can only understand IP Addresses and provide a mail server list that usually accepts emails for each domain name. Each domain name registered in the Domain Name System (DNS) designates a group of name servers as authoritative for its DNS records. For instance, when a user enters a web address (URL) in a web browser, the DNS system is queried to obtain the IP address of a web server linked to that domain name.

  1. State the difference between compiler, interpreter, and assembler.

The primary difference between a compiler, an interpreter, and an assembler is:

  • A compiler will transform the entire high-level language into machine language at a time.
  • An interpreter differs from a compiler and an assembler because it transforms high-level language programs into machine language line by line.
  • A reason that makes an assembler different from the compiler and an interpreter is that it transforms the assembly language programs into machine language.
  1. List a few OOPs concept-based languages.

C++, Java, Python, and C# are some of the OOPs concept-based languages.

  1. What operating system do you prefer the most and why?

Software engineers can reference operating systems such as Unix, Linux, or Windows. For instance, Linux is known for its speed and efficiency. Windows, on the other hand, boasts a clean user interface that is used to enable users to manage multiple tasks and monitor on-screen activities easily.

  1. Can a class be final?

Yes, a class can be final. But a final class can’t generate a subclass.

  1. Can a class be private?

A top-level class can’t be private since if it is not accessed, it will be useless. Indeed, a nested or an inner class can be marked as private because the outer class can access it.

  1. Define a collection framework.

The purpose of a collection framework is to permit storage and retrieval of a group of objects that can be seamlessly modified, searched, removed, sorted, or added. For instance, List, Map, Set, etc.

  1. Explain the function of HashMap.

The HashMap operates based on the hashing principle, in which an object is transformed into an integer representation using the hashCode() method. The get(key) method is employed to invoke the hashCode method. Subsequently, the resulting hash value is utilized to locate the bucket where the key-value pairs are stored as entry objects.

  1. What is StringBuffer, and how does it differ from String?
  • StringBuffer is a class used to create editable string objects, allowing various string manipulations such as reversing, concatenation, and appending.
  • Unlike the String class, StringBuffer is mutable.
  • String objects consume more memory compared to StringBuffer.
  • When it comes to concatenation operations, StringBuffer is faster.
  • StringBuffer utilizes heap memory, whereas String uses the String Constant Pool for storage.
  1. Define threads.

In OS, multiple processes are performed simultaneously. These processes are further divided into small execution units called threads. These threads permit parallel processing, which makes the system fast. Threads have their resources for execution and memory allocation. Threads are categorized into two types:

  • User threads.
  • Kernel threads.
  1. Define pass-by-reference.

Passing by reference allows a function to alter a variable without duplication. This approach requires the declaration of reference variables. The passed variable and parameter reference the same memory location, and any modification to the parameter is likewise mirrored in the variable.

  1. What is a function pointer?

A function pointer is referred to as a pointer to a function that points to a code. These function pointers are used in passing the function’s address to another function or in the implementation of a callback mechanism.

  1. Explain many constructors you can create with a class TestSample.

Usually, there is no set limit to the count of constructors that a user can generate as long as the constructor holds a different parameter set. In the case of the TestSample class, it is possible to define the default constructor TestSample() and any other constructors.

  1. Define a static keyword.

A static keyword can be used when one needs more than one object to reuse the same value of a variable. A static variable defined within a class is associated with the class itself rather than with individual objects. Hence, it is necessary to instantiate the class to access the variable.

  1. Define postfix and prefix operators.

The ++ and — operators can be employed as either pre or postfix operators. When used as ++i, the counter is incremented first, and the subsequent action is carried out. In contrast, when used as i++, the next action is executed first, followed by an increment in the i value.

  1. What are the main demerits of an indexed sequential file?

The main demerits of an indexed sequential file are given below:

  • If the number of records increases, the level of performance will be decreased.
  • The deleted records will be excluded if the indexed records are reorganized.
  • Indexed records consume a large disk space.
  1. State the difference between a private cloud and a public cloud and explain which one is better.

In a private cloud setup, data security is ensured through a firewall, and the data is stored within the company’s hosted data center. While this option is costly, it offers a high level of security.

On the other hand, in a public cloud arrangement, the data is managed and maintained by the cloud service provider. This approach reduces deployment and testing responsibilities for the client, resulting in lower overhead costs. Although public clouds provide a lower level of security than private clouds, they are favored for their cost-effectiveness.

  1. State the difference between the static method and the instances method.

In static methods, it is not possible to override because the function of this method is restricted within the class and area. On the other hand, the instance method is linked to the object, and it belongs to the heap area.

  1. Is it necessary for every class to have a constructor?

Yes, every class must have a constructor because it carries out a procedure. The procedure is known as object initialization used to initialize an object. So, every class should have a constructor.

  1. State the difference between the Primary and a Unique key.

The table should have a minimum of one key to have a primary key because it can prevent null values and duplicates. In contrast to a unique key, it is possible to have more than one key in the database for the procedure. It is used to accept null values but prevents duplicate ones.

  1. Define DBMS.

DBMS (Database Management System) is a software used to capture and analyze data through interaction with the application, database, and users.

  1. Define Polymorphism.

As the name says, the root word – poly is known as many, and morphism is known as forms. Polymorphism will help a user build diverse shapes with one usage of a function to make it unique. In Java, polymorphism is used for many class and object types by using a single piece of an interface, and it is a factor that distinguishes polymorphism from other aspects.

Given below are the HCL interview questions with codings.

  1. What is the purpose of the finalize () method in Java?

In Java, the finalize() method holds a unique status akin to the primary method. It serves as the last opportunity for an object to execute cleanup tasks before the garbage collector reclaims it. This process involves releasing any resources held in a fixed order and closing an open connection, among other necessary activities.

For instance:

protected void finalize() throws Throwable {


  1. What is the purpose of Polymorphism in Java?

Polymorphism is a fundamental requirement in Java due to its extensive application in inheritance. It plays a vital role in enabling objects with distinct internal structures to have a common external interface.

For instance:

class Animal{

void makeSound(){System.out.println(“Some animal sound”);}


class Dog extends Animal{

void makeSound(){System.out.println(“Barking”);}


public class PolymorphismExample {

public static void main(String[] args) {

Animal myPet = new Dog();




In the above example, “class Dog extends Animal” denotes that the class Dog is inherited within the class Animal. With this, new internal structures can be generated within the same external class.

  1. Explain the difference between a constant and a global variable.

Constant variables maintain a consistent value that remains unaltered throughout the program, while global variables are mutable and accessible to all functions within a program. Here is a paraphrased version of the content:

For example:

#include <stdio.h>

int globalVar1 = 20, globalVar2 = 40; // Global variables

int globalVar3 = 50, globalVar4 = 80; // Global variables

void sample() {

int localVar = 20; // Local variable


int main() {

printf(“These variables are accessed from the main function”);

globalVar3 = 24;



In this code, we have global and local variables, with a function called sample that defines a local variable. The global variables are accessible and can be modified within the primary function, and the local variable is restricted to the sample function’s scope.

  1. What are nested classes?

Nested classes refer to the capability of defining a class within another class within an Object-oriented programming language (OOP). The class enclosed within is termed a nested class. It shares the same access privileges as other members of the enclosing class and is considered a part of the outer class.

For example:

class Department {


int deptID;

class Employee {


int empID;

void display() {

std::cout << “Employee ID: ” << empID << “, Department ID: ” << deptID << std::endl;




void assignIDs(int dept, int emp) {

deptID = dept;

Employee empObj;

empObj.empID = emp;




In this example, the Inner class is nested inside the Outer class, and the inner class shares access rights with the outer class. Nested classes are used for organizing classes within a common group.

  1. Explain how to achieve Multiple Inheritance in Java with an example.

Implementation of multiple inheritance is achieved through the implementation of multiple interfaces in a class. In Java, a single class can implement 2 or more interfaces. As all the declared interface methods are implemented in the class, it won’t cause ambiguity.

Example Coding:

// First Interface

interface Parent1 {

void fun1();


// Second Interface

interface Parent2 {

void fun2();


public class Test {

public static void main(String[] args) {

// Implementing the first interface using an anonymous inner class

Parent1 parent1 = new Parent1() {

public void fun1() {




// Implementing the second interface using another anonymous inner class

Parent2 parent2 = new Parent2() {

public void fun2() {




// Calling the methods from the interfaces





In this alternative code, we implement the interfaces using anonymous inner classes and call the methods from those interfaces, achieving the same result as the previous code.

  1. Define init in Python.

Generally, ‘init stands for initialization. The purpose of init is to generate processes from the script saved in the configuration file. The initialization system will use this process. The init method is the same as the constructor in Java and C++.

Example Coding: 

class MyClass:

def __init__(self, name):

self.name = name

# Usage

obj = MyClass(“John”)


In the above code, we define a class MyClass with an __init__ method that takes the name parameter. When an instance of the class is created (e.g., obj = MyClass(“John”)), the name attribute is initialized with the provided value. You can access the name attribute as shown in the print statement.

  1. Write a program coding to reverse a string.

Given below is a C program that takes an input string from the user by using strrev method.

Example coding:

#include <stdio.h>

#include <string.h>

int main() {

char chrarr[100];

printf(“Enter the string: “);

if (fgets(chrarr, sizeof(chrarr), stdin) == NULL) {

perror(“Input error”);

return 1;


// Remove the trailing newline character

chrarr[strcspn(chrarr, “\n”)] = ‘\0’;

int length = strlen(chrarr);

// Reverse the string

for (int i = 0, j = length – 1; i < j; i++, j–) {

char temp = chrarr[i];

chrarr[i] = chrarr[j];

chrarr[j] = temp;


printf(“Reverse of the entered string is:\n%s\n”, chrarr);

return 0;


  1. Write a query to fetch only the first 3 records from a database.

Using the rownum keyword, you can fetch the first 3 records in Oracle:


FROM your_table


Given below is the query to show how the keyword limit is used in MySQL.


FROM your_table


Given below are HCL interview questions with the listing format.

  1. What is Big Data?

Big data are large volumes of data. The data that are available on several online platforms are vast and complex. It is a challenging task for traditional systems to process, analyze and interpret the data. Big data helps in solving a lot of business issues, like machine learning, customer service, and predictive maintenance.

Given below are certain the features of big data:

  • Velocity
  • Volume
  • Value
  • Variety.
  • Veracity.
  • Validity.
  • Volatility.
  • Visualization.
  1. List some software analysis & design tools.

Given below are the essential software analysis and design tools.

  • Data Flow Diagrams
  • Structured Charts
  • Structured English
  • Data Dictionary
  • Hierarchical Input Process Output diagrams
  • Entity Relationship Diagrams and Decision Tables.
  1. What is DBMS?

The DBMS (Database management system) is a software/ tool used to manage the entire data of a company or an organization. Using a Database management system (DBMS), a vast amount of data can be stored and presented whenever required to make business-related decisions.

Given below are some of the features of a Database management system (DBMS):

  • Database Customization.
  • Easiness in Data Management.
  • Data Availability.
  • Minimized Redundancy.
  • Data Accuracy, Consistency and Relevance.
  • File Consistency.
  • Improved Data Security.
  • Data Structuring.

A few examples of DBMS are MySQL, PostgreSQL, FileMaker, Oracle, and Microsoft Access.

Given below are the HCL interview questions in listing format with the explanation.

  1. Explain the different types of cloud computing service models.

Cloud Computing Service Models

The diverse types of Cloud computing service models can be categorized as below:

  • Infrastructure as a Service (IaaS): IaaS represents internet-managed computing infrastructure
  • Platform as a Service (PaaS): The PaaS involves a cloud computing platform designed for programmers to create, test, deploy, and oversee applications.
  • Software as a Service (SaaS): SaaS involves cloud service providers hosting applications.
  • Function as a service (FaaS): FaaS offers a platform enabling customers to develop, operate, and oversee application functions without the intricate task of constructing and upkeeping associated infrastructure during the application launch process.
  1. What are the purposes of a Pointer in C?

Uses of Pointer

Given below are the uses of Pointer in C.

  • Accessing array elements: Pointers are utilized for navigating arrays of integers and strings. Strings are sequences of characters terminated by the null character ‘\0’.
  • Dynamic memory allocation: Pointers are used for allocating and deallocating memory during the program execution.
  • Call by reference: It passes the reference from one function to another.
  • Used in Data Structures: Pointers are crucial in building various data structures such as graphs, trees, linked lists, and more.
  1. List the 4 pillars of Object-oriented programming systems (OOPs).

Properties of OOPs

The 4 main properties of Object-oriented programming systems (OOPs) are as follows:

  • Inheritance: Inheritance is used by an object to inherit some or all properties of another object.
  • Abstraction: This property is used to select data and show only its necessary information and hide the rest.
  • Encapsulation: This property is achieved when each object inside a class maintains a private state. When each object in class maintains a private stare, it is known as Encapsulation.
  • Polymorphism: This property uses a class like its parent to avoid mixing types.
  1. Define aggregate functions in SQL.

A function is referred to as a unit of code that is used for reusing a part of a program. An SQL aggregate function is helpful to calculate a set of values and return a single value. The function should return a value.

Some SQL aggregate functions are given below.

  • AVG(): This function computes the average of a set.
  • COUNT(): It determines the count or number of items in a set.
  • MAX(): It identifies the maximum value within a set.
  • MIN(): It identifies the minimum value within a set.
  • SUM(): It calculates the total sum of values, whether they are distinct or not, within a set.
  1. Define Constraints in SQL.

In SQL, Constraints are rules that can be applied to the various data types in a given table. It is used to check the reliability and accuracy of the data in the table.

Given below are the types of Constraints in SQL.

  • NOT NULL: The NOT NULL constraint is used when one cannot store a null value within a column.
  • UNIQUE: This UNIQUE constraint is used when all the values in a given column must be unique when specified with a column.
  • PRIMARY KEY: It is a field designated to uniquely identify each row within a table, serving as a means of specifying which field in the table holds this distinctive role.
  • FOREIGN KEY: It is a field that can uniquely identify individual rows within a different table.
  • CHECK: This constraint aids in validating the values of a column to ensure they meet specific conditions.
  • DEFAULT: This constraint provides a default value for a column when the user omits specifying a value.
  • DEFAULT: This constraint provides a default value for a column when the user omits specifying a value.
  1. Name the various types of data in C.

The 5 major types of data types in C:

  • Primary data type: Floating-point, integer, double, character.
  • Derived data type: Union, structure, array, pointers.
  • Enumerated data type: Enums.
  • Void data type: Empty value.
  • Bool Type: True or False.
  1. Define SQL joins. 

SQL joins fetch data from different tables as a single record using common columns and foreign keys.

Given below are the 4 primary types of joins in SQL.

  • JOIN (INNER): It retrieves records with corresponding values in both tables.
  • RIGHT (OUTER) JOIN: In a RIGHT JOIN, all records from the right table are retrieved along with the matching records from the left table.
  • LEFT (OUTER) JOIN: It retrieves all records from the left table and the matching records from the right table.
  • FULL (OUTER) JOIN: It retrieves all records in the event of a match in either the left or right table.

Below are the HCL interview questions that state the differences between the 2 topics.

  1. State the difference between C and Java.
C Java
C is more procedure-oriented. Java leans towards being data-oriented.
C falls into the category of middle-level languages, bridging the gap between machine-level and high-level languages. Java is considered a high-level language since it translates code into machine language using a compiler or an interpreter.
C typically organizes code into functions. Java organizes code into objects.
In C, memory allocation is achieved using malloc. In Java, memory allocation is accomplished with the new keyword.
C lacks support in the concept of ‘threading’. Java provides robust support for multithreading.
C supports the use of pointers. Java does not offer that feature.
  1. State the differences between C and C++
C C++
C lacks inheritance support. C++ includes support for inheritance.
C places greater emphasis on methods or procedures. C++ gives higher priority to data.
In C, input/output operations are typically managed using the scanf() and printf() functions. In C++, input/output is achieved using cin and cout.
C does not offer support for reference variables. C++ does support reference variables.
Exception handling is not present in C. Exception handling is a feature of C++.
C structures do not have access modifiers. C++ structures incorporate access modifiers.
  1. State the difference between ApplicationContext and BeanFactory.
ApplicationContext BeanFactory
It employs eager or aggressive initialization. It employs lazy initialization.
It offers support for internalization (i18n). It lacks support for internalization (i18n).
It supports dependency injection using annotations. It does not provide support for dependency injection using annotations.
It automatically registers BeanPostProcessors. It requires manual registration of BeanPostProcessors.
  1. State the significant difference between HashTable and HashMap.
HashTable HashMap
HashTable is synchronized. HashMap lacks synchronization.
HashTable does not permit null keys or values. A HashMap allows for a single null key and multiple null values.
HashTable exhibits slower performance. HashMap demonstrates faster performance.
HashTable can be iterated by using both iterators and enumeration. HashMap can be iterated by using iterators.
HashTable is derived from a dictionary class. HashMap is derived from the AbstractMap class.

  1. What sets overloading apart from overriding?
Overloading Overriding
Overloading, in the context of methods or variables, involves using the same name but with different signatures. Overriding, on the other hand, is about using the same name and signature for parameters.
Overloading is a compile-time concept, checked during compilation. Overriding, in contrast, is a runtime concept verified during program execution.
Overloading takes place within a single class. Overriding typically occurs in two classes related to inheritance.
In overloading, it’s essential to have different argument lists. In overriding, the argument list must remain the same.

In conclusion, HCL is a prominent company that provides IT and consulting services. HCL also provides strategic guidance on Digital, Automation, Analytics, Cloud, IoT, Cybersecurity, Infrastructure Management, and Engineering Services. It also operates across various sectors like banking, automotive, healthcare, etc. This blog will guide job-seeking candidates with HCL interview questions.

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