Working at HCL is a dream for many software engineers who focus on innovation. HCL interview questions help aspirants get familiar with what they might encounter in their interview. The HCL interview process is set to root out engineers with a self-starter mentality and a solid technical background. The company’s ideal candidate is someone who learns from their mistakes, quickly grasps new things, and comes up with inventive ideas. Prepare the most anticipated HCL interview questions to nail the most challenging rounds. 

About HCL

HCL Technologies is a leading IT service and consulting company helping enterprises shape their businesses for the digital age. Operating in 50+ countries, HCL is headquartered in Noida, India. The company provides innovative solutions around Digital, Cloud, Infrastructure Management, Analytics, IoT, Cybersecurity, Automation, and Engineering Services, securing its place on the Forbes Global 2000 list.

HCL Interview Process 

HCL seeks new talented candidates via a selection process comprising four rounds:

  • Written/Aptitude Assessment Round

The first round is online, involving questions around quantitative ability and verbal reasoning in the form of MCQs, usually for freshers and not for experienced individuals. 

  • Group Discussion

The recruiter assesses a candidate's personality traits such as problem-solving skills, team spirit, ability to come up with instant solutions, conflict resolution, and more by forming teams and providing a common topic of discussion. 

  • Technical Interview Round

Software engineers are asked questions on crucial topics like Java, C, C++, UNIX, LINUX, Data Structures, Algorithms, etc., to judge their fundamental and advanced knowledge. Experienced individuals should be prepared for questions about their past experiences based on their resumes. 

  • HR Round

The final round has scenario-based behavioral questions. The recruiter evaluates a candidate's interest in joining the organization and their personal goals and ambitions. 

HCL Technical Interview Questions: Freshers and Experienced

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

Finalize () method is called as the last chance for an object to carry out a cleanup activity before the garbage collector reclaims it. It involves releasing any fixed order resources held, termination of a connection if open, and more. 

2. What is the role of polymorphism in Java?

Polymorphism is extensively used in implementing inheritance. It allows the object with a different internal structure to share the same external interface. 

3. What is input-output (I/O) in C++?

I/O stream is the standard input-output stream in C++ containing cin, cout, and other methods. The input stream allows inputs from the console/user. The output stream displays the operations’ results to the user or output device. 

4. State major differences between a constant variable and a global variable?

Constant Variable 

Global Variable

It has a fixed value that cannot be changed throughout the program.

It can be changed and is accessible by all the functions in a program.

5. What do you understand about nested classes?

Object-oriented programming languages allow defining a class inside another class. The enclosed class is the nested class. It has the same access rights as other class members serving as another member of the outer class.

6. What is cloud computing? How is it useful today?

Cloud computing is the technique of storing, processing, and managing data in a shared network of remote servers over the internet. The data is distributed and hence more secure. Cloud computing offers flexible resources, innovation, and economies of scale.

7. What are the different cloud computing service models?

  • IaaS (Infrastructure as a Service): A computing infrastructure managed over the internet.
  • PaaS (Platform as a Service): Cloud computing platform for developing, testing, running, and managing applications.
  • SaaS (Software as a Service): A cloud service provider hosts applications. 
  • FaaS (Function as a service): A platform for developing, running, and managing app functionalities without the need for building and maintaining app launching infrastructure. 

8. What is Big Data?

Big data refers to large data sets too complex for traditional data-processing application software. The features of big data are:

  • Velocity
  • Variety
  • Volume
  • Value
  • Veracity
  • Visualization
  • Validity
  • Volatility

9. Name some software analysis and design tools.

Some software analysis and designing tools are:

  • Data Flow Diagrams
  • Data Dictionary
  • Structured Charts
  • Structured English
  • Entity Relationship Diagrams and Decision tables
  • Hierarchical Input Process Output diagrams

10. How is structured English different from Pseudo Code?

Structured English employs the native English language to provide the structure of a program module, using programming languages’ keywords. Pseudo Code is like a programming language lacking the syntax of any specific language.

11. What is the role of the pointer in C?

Pointer in C are used for the following purposes:

  • To access array elements
  • For dynamic memory allocation and deallocation while the program is executed
  • Call by reference
  • To construct several data structures like trees, graphs, linked lists, and so on

12. What are the major differences between C and C++?





It supports inheritance.

It does not support inheritance.


It focuses on data instead of method or procedure.

It focuses on a method or process rather than data.

Access Modifiers

It has access modifiers. 

Structures lack access modifiers. 

Exception Handling

It supports exception handling.

It does not support exception handling.

Reference Variables

It supports reference variables.

It doesn’t.

Input/output functions

cin and cout

scanf() and printf() functions

13. What are the four pillars of object-oriented programming systems (OOPs)?

The pillars of OOPs are as follows:

  • Inheritance: Basing an object or class upon another class/object.
  • Abstraction: Selecting data from a pool to show only the relevant details to the object.
  • Encapsulation: Wrapping data in a single unit.
  • Polymorphism: Allows using class exactly like its parent to avoid confusion.

14. What are aggregate functions in SQL?

An aggregate function relies on a set of values to return a single value. Following are some SQL aggregate functions:

  • AVG() gives the average of a set
  • MIN() gives the minimum value in a set
  • COUNT() returns the number of items in a set
  • MAX() returns the maximum value
  • SUM() returns the sum of distinct/all values in a set

15. What do you understand about constraints in SQL?

Constraints are the rules or limits applied to the different data types in a given table to ensure its accuracy and reliability. SQL constraints are as follows:

  • NOT NULL: Informs no null value can be stored within a column
  • UNIQUE: Informs all the values in the column should be unique
  • PRIMARY KEY: The field that uniquely identifies each row in a table
  • FOREIGN KEY: The field that uniquely identifies each row in another table
  • CHECK: It helps validate the column values for attaining a particular condition
  • DEFAULT: It gives a default value for the column when the user doesn't specify one

16. What do you mean by DBMS?

The Database Management System is a software for managing the entire organization's data, including its proper storage and presentation whenever required for business decisions. E.g. MySQL, Oracle, PostgreSQL, FileMaker, and Microsoft Access. The features of DBMS are:

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

17. How would you achieve multiple inheritances in Java?

Implementing multiple interfaces in a class is the only method to achieve multiple inheritances in Java. The process does not cause ambiguity as all methods declared in interfaces are implemented in the class. 

18. What is init in Python?

In Python, ‘init' stands for initialization. This method creates processes from the script stored in the configuration file used by the initialization system. It is similar to constructors in Java.

19. What is the use of a Domain Name System (DNS)?

The primary role of DNS is to translate domain names into IP addresses that computers can understand so that the initiating client can load the requested Internet resources. It also lists mail servers accepting emails for every domain name. 

20. What are the major points of difference between C and Java?



It is more procedure-oriented.

It is more data-oriented.

It is a middle-level language as it often has gaps between machine level language and high-level languages.

A high-level language that uses a compiler or interpreter to translate code into machine language. 

It breaks down into functions.

It breaks down to objects.

Memory allocation can be done by malloc.

It is done by a new keyword.

It doesn’t support threading.

It supports threading.

It supports pointers.

It doesn’t support pointers.

21. What is the difference between interpreter, compiler, and assembler?

  • Compiler: It converts the whole high-level language program to machine language at a time. 
  • Interpreter: It converts high-level language programs to machine language line by line. 
  • Assembler: It converts assembly language programs to machine language.

22. Which languages are based on OOPS concepts?

C++, Java, Python, and C# are based on OOPs concepts

23. What operating systems have you worked with? Which one do you prefer the most and why?

Software engineers can mention Unix, Linux, Windows, or any other operating system, along with advantages while answering this HCL interview question. For example, Linux is fast and efficient. Windows has a neat UI enabling its users to clearly view all that’s happening on the screen while multitasking. 

24. Can a class be final? 

Yes, a class can be final, and its subclass cannot be created.

25. Can a class be private?

Nested/ inner classes can be private as the outer class can access them. A top-level class cannot be private as it would be completely useless when none would have access to it.

26. What is the collection framework?

A collection framework allows storage and retrieval of a group of objects that can be easily modified, searched, removed, sorted, or added. For example, List, Map, Set, etc. 

27. Explain how HashMap works.

HashMap works on the hashing principle wherein an object is converted into integer form using the hashCode() method. The hashCode method is called using the get(key) method. The returned hash value is then used to find the bucket location of the key-value pairs stored as entry objects. 

28. How is the application context different from the bean factory?

Application Context

Bean Factory

It uses eager/aggressive initialization. 

It uses lazy initialization. 

It supports internalization (i18n).

It doesn’t support internalization (i18n).

It supports annotation-based dependency.

It doesn’t support annotation-based dependency..

It has automatic BeanPostProcessor registration.

It has manual BeanPostProcessor registration.

29. What is StringBuffer? How is it different from String?

StringBuffer is a class for creating modifiable string objects. Using the StringBuffer class, one can perform several string operations like reversing, concatenation, appending, and more. 

  • StringBuffer is mutable while the String class is immutable.
  • String consumes more memory than StringBuffer. 
  • Concatenation operations are faster in StringBuffer. 
  • StringBuffer uses heap memory while String uses String Constant Pool for storage.

30. What are the major differences between a hashtable and a hashmap?



It is synchronized. 

It is not synchronized.

It doesn’t allow any null key or null value.

It allows one null key and multiple null values.

It is slow.

It is faster.

It is traversed by iterator and enumeration.

It is traversed by iterators.

It inherits a dictionary class.

It inherits the AbstractMap class.

31. Write a program to reverse a string.

The following is a C program that takes an input string from the user. The strrev method is used in this program. 



int main()


 char chrarr[100];

 printf("Enter the string \n");



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

 return 0;


32. What are threads?

An OS has multiple processes going on simultaneously. These processes are divided into small execution units called threads. They allow parallel processing making the system fast. Threads possess their resources for execution and memory space. The two types of threads are: 

  • User threads
  • Kernel threads

33. What is a pass by reference? 

Pass by reference allows a function to modify a variable without creating a copy. One has to declare reference variables. The passed variable and parameter share the same memory location, and any change to the parameter is also reflected in the variable.

34. How is overloading different from overriding?



Overloading a method/variable means using the same name but a different signature. 

Overriding a method/variable means using the parameters (name and signature).

It is checked during compile time.

It is a run-time concept.  

It occurs within the class.

It is in two classes with inheritance. 

It must have different argument lists.

It must have the same argument list.

35. What do you understand about a function pointer?

A pointer to a function is referred to as a function pointer. Unlike normal pointers that point to data, a function pointer points to code. They are very useful for passing the address of a function to another function or implementing a callback mechanism.

36. How many constructors can you create if you have a class TestSample?

There isn't a set limit to the number of constructors that one can create as long as the constructors have a different set of parameters. For the TestSample class, the default constructor TestSample() and any other constructors can be defined.

37. What is the static keyword?

A static keyword is applicable when a user requires more than an object to reuse the same value of a variable. A static variable declared inside a class is the variable of the class, not the object. Therefore, one must create an instance of the class to use the variable. 

38. What are the different types of data in C? 

The five major categories of data types in C are as follows: 

  • Basic 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

39. What are postfix and prefix operators?

The ++ and -- operators are used as pre or postfixes. ++i first increments the counter and then performs the next action, whereas i++ performs the next action and then increments the value of i.

40. What are SQL joins? 

SQL joins are useful for fetching data from various tables as a single record employing common columns and foreign keys. The four main types of joins are: 

  • (INNER) JOIN: Returns records with matching values in both tables.
  • RIGHT (OUTER) JOIN: Returns all records from the right table and the matched records from the left.
  • LEFT (OUTER) JOIN: Returns all records from the left table and the matched records from the right. 
  • FULL (OUTER) JOIN: Returns all records in case of a match in either left or right table

41. Write a query to fetch only the first three records from a database.

Using the rownum keyword, one can fetch the first three records in Oracle: 

select * from (select * from student order by student_id) where rownum <=3;

In MySQL, the keyword limit is used as follows: 

select * from student order by student_id limit 3

42. What are the major disadvantages of an indexed sequential file?

The major disadvantages of an indexed sequential file are as follows:

  • An increase in the number of records decreases the performance.  
  • The indexed files must be reorganized, so that deleted records are excluded. 
  • It consumes significant disk space.

43. How is a private cloud different from a public cloud? Which one is better?

A private cloud protects all the data by a firewall. The data resides in the company's hosted data center. It is an expensive but secure option. In a public cloud, the data stays with the cloud service provider who takes care of the data center's management and maintenance. It reduces the overhead of deployment and testing for the client. Although a public cloud offers less security than a private one, it is preferred because it is less expensive.

44. What is the difference between the static and instance methods?

The static method cannot be overridden as the function of this method is restricted within the class and area. However, the instance method belongs to the heap area and is linked to the object.

45. Does every class require a constructor?

Yes, every class requires a constructor as it carries out a procedure, which is called object initialization for the purpose of initializing the object. Therefore, every class essentially needs a constructor.

46. What is the difference between the Primary key and a Unique key?

The table should have at least one key in order to have a primary key. You can prevent null values and duplicates using this key. On the other hand, there can be more than one key in the database for the unique key procedure, which is useful for accepting null values and preventing duplicate ones.

47. What is DBMS?

DBMS is the abbreviation for Database Management System. It is software used for capturing and analyzing data by interacting with the applications, database, and users.

48. What is polymorphism?

The concept of polymorphism can be understood through the meaning of its root words- poly means many and morphism means forms. Polymorphism enables users to construct various different shapes with a single usage of a function, thus making it quite unique. In Java language, polymorphism is mainly used for processing several class and object types using a single piece of an interface, which is a distinguishing factor of polymorphism.

49. What is synchronization?

Synchronization is a process that allows threads to run one after another. Synchronization utilizes different threads to regulate access to shared resources.

50. What are nested classes?

A nested class in an object-oriented programming language allows you to define a class within another class. Therefore, a class that is enclosed within another class can be defined as a nested class. A nested class, just like its outer class member, has the same access permissions as the rest of the functions and classes.

51. What are the four pillars of Java?

Following are the four pillars of Java-

Inheritance – Inheritance allows an item to inherit all or some of the properties and features of another object.

Abstraction – When you pick data from a pool of data and display only the features relevant to the item, the process is known as abstraction.

Encapsulation – You can achieve encapsulation when every object in a class retains its private state.

Polymorphism – You can utilize a class identical to its parent without encountering type confusion upon using polymorphism.

52. What is the difference between structured English and Pseudo Code?

The structure of a program module utilizes Structured English, which is a native speaker. It also makes use of programming language keywords. Pseudo Code, on the other hand, does not have a specific syntax of a certain language.

53. What is the use of the finalize () method in Java?

Finalize () is a specific method similar to how the main method functions in Java. This function is used as the last attempt of an object to clean up. After the finalize () function is used, the garbage collector automatically reclaims the object. Using the finalize () function involves fixing order resources, closing connections that are open, and much more.

54. What is stack unwinding?

Stack unwinding is a practice that involves the removal of functional entries from the call stack function when it is runtime. Stack unwinding is often related to Exception Handling. There is a linear search conducted for the exception handler using the function call stack upon the occurrence of a C++ exception. Followed by this, the entries that precede the function with exception handler are eliminated. When the exception is not handled in the same function, stack unwinding becomes essential.

55. What is a peep stack?

A peep stack is an action or a stack function that is used for returning the value of the top-most element of a stack without the removal of this element from the stack.

56. What is the Collection framework?

A collection framework stores and retrieves a group of objects. Objects stored in a collection are easy to modify, search, sort, add, and remove. There are several examples of collection frameworks, such as Map, Set, and List, among others.

57. Can you explain how HashMap works?

To call the hashcode method, it is first required to call the get(key) method. Upon doing this, the hashcode method is called which returns the value of the hash. This returned hash value is used for finding the bucket location of the key value pairs stored as entry objects. Since HashMap is not synchronized, it is not thread-safe.

58. What is the difference between Application context and bean factory?

There are two containers provided by the Spring framework for dependency injection, which is Application Context and BeanFactory. While BeanFactory offers basic features, Application Context is feature-rich and can do a lot more compared to BeanFactory. Moreover, Application Context is a preferred choice for real-time applications. Application Context also supports internalization.

59. What is StringBuffer and how is it different from String?

StringBuffer is a class that can be used for creating String objects which can be modified. StringBuffer class allows you to carry out several string operations such as reversing, appending, concatenation, etc. While StringBuffer can be mutable, meaning the above operations can be performed on the same object, the String class is immutable. String consumes more memory than StringBuffer, and the concatenation operations are faster on StringBuffer as the objects are stored in heap memory.

60. Can you implement a linked list?

Yes, a linked list can be implemented using the node class. There are three functionalities that are used for the implementation of a linked list, which is as follows-

  • Insertion at start position
  • Insertion at end position
  • Insertion at the required position

61. What are threads?

There is a range of processes happening simultaneously in every operating system. For instance, a user can be browsing the internet, typing a document, and listening to music all at the same time. These processes are divided into various threads, which are small execution units that make it possible to process these functions parallely, thus making your system fast and efficient. Threads have their own resources and memory space for execution. Further, there are different types of threads, such as kernel and user threads.

62. What is a function pointer?

A pointer to a function is known as a function pointer. Unlike normal pointers that point to data, functional pointers point to codes. They’re a useful function for passing the address of one function to another or for implementing a callback mechanism.

63. What are virtual functions?

Virtual functions are used in C++. They are declared in the base class and are used as member functions. They are both defined and redefined by the derived class. This simply means that you can override a virtual function by the derived class.

64. How many constructors can you create if you have a class TestSample?

There is no specific limit that is set when it comes to creating constructors. However, the constructors created, irrespective of the number, should have a different set of parameters.

65. What is the difference between a constant and a global variable?

While global variables can be accessed and modified by all the functions in a program, constant variables cannot be changed throughout the program as they have a fixed value.

66. What are postfix and prefix operators?

Postfix operations and prefix operations are denoted using the following operators respectively: ++ and - -. While these operators can be used as prefix or postfix, what is different for both is the results. While ++i causes an increment in the counter before performing the next action, i- - first performs the next action, followed by which there is an increment in the value of i.

67. What is the difference between compiler, interpreter, and assembler?

While the compiler is used for converting a complete high-level language program to machine language at once, an interpreter converts the same line by line. Assembly language programs can be converted to machine language using an assembler.

Frequently Asked Questions

1. Is HCL interview easy?

The difficulty of an HCL interview varies in difficulty based on how prepared you are. Therefore, it is best to be well-prepared and go through the most common interview questions to build confidence.

2. How many interview rounds are there in HCL?

The interview process comprises 4 rounds, which are written or aptitude assessment round, group discussion, technical interview round, and HR round.

3. How do I qualify for an HCL interview?

It is crucial to meet the eligibility criteria for securing a job at HCL, which is a minimum score of 60% in academics through 10th and 12th grade and graduation and post-graduation. You should not have an education gap of more than a year. Having a good knowledge of C, C++, and Java can help you qualify for an HCL interview.

4. What is the salary for freshers in HCL?

The average salary of freshers at HCL Technologies ranges from INR 1,60,000 to INR 4,00,000 per annum in India. 

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