30+ HCLTech Software Engineer Interview Questions and Answers for Freshers

Difference between server.transfer and Response.redirect

• Server.Transfer transfers control to another page on the server without the client knowing

• Response.Redirect sends a message to the client to redirect to another page

• Server.Transfer is faster and more efficient than Response.Redirect

• Server.Transfer can only be used within the same application, while Response.Redirect can be used to redirect to any URL

The interview questions cover various topics related to Spring framework, REST vs SOAP, JPA repository, Feign client, circuit breaker, and Spring Security.

• Spring Boot provides a simpler and faster way to set up and run Spring applications compared to traditional Spring.

• Common annotations in Spring include @Controller, @Service, @Repository, @Autowired, @Component, @RequestMapping, @GetMapping, @PostMapping, @PutMapping, @DeleteMapping, @Valid, @NotNull, etc.

• CRUD operations re...read more

Interview questions for Software Engineer position covering OOPS concepts, exception handling, SOLID principles, Java 8 features, and Streams.

• Abstraction in OOPS: Hiding implementation details. Example: Abstract class Shape with method draw().

• Encapsulation in OOPS: Bundling data and methods that operate on the data. Example: Class Employee with private fields and public getters/setters.

• Inheritance in OOPS: Reusing code and extending functionality. Example: Class Dog extends A...read more

String pool is a cache of string literals in Java. String is immutable to ensure security and efficiency.

• String pool is a collection of unique string literals stored in heap memory.

• When a new string is created, JVM checks if it already exists in the pool. If yes, it returns the reference to the existing object.

• String immutability ensures that once a string is created, its value cannot be changed. This ensures security and efficiency.

• For example, if a password is stored as a s...read more

if else is used for conditional statements with multiple conditions while switch is used for multiple conditions with same variable.

• if else can handle multiple conditions with different outcomes

• switch can handle multiple conditions with same outcome

• if else is more flexible and can handle complex conditions

• switch is faster and easier to read for simple conditions

• example of if else: if (x > 5) {do something} else if (x < 5) {do something else} else {do something else}

• example of...read more

Executor is an interface that executes submitted tasks in a separate thread. Thread pool is a collection of threads that can be reused.

• Executor provides a way to decouple task submission from task execution.

• Thread pool manages a fixed number of threads and assigns tasks to them.

• Executor framework provides a way to manage thread pools.

• Example: Executors.newFixedThreadPool(10) creates a thread pool with 10 threads.

• Example: Executor.execute(Runnable task) submits a task to the e...read more

Jagged arrays are arrays of arrays with different lengths.

• Jagged arrays are also known as ragged arrays.

• They are useful when the number of elements in each row is not fixed.

• Example: int[][] jaggedArray = new int[3][]; jaggedArray[0] = new int[2]; jaggedArray[1] = new int[4]; jaggedArray[2] = new int[3];

• Accessing elements in a jagged array requires two sets of square brackets.

• Jagged arrays can be used to represent irregularly shaped data, such as a matrix with missing values.

OOPs (Object-Oriented Programming) is a programming paradigm based on the concept of 'objects', which can contain data and code.

• OOPs focuses on the use of classes and objects to organize and structure code

• Encapsulation, inheritance, and polymorphism are key concepts in OOPs

• Examples of OOPs languages include Java, C++, and Python

Data structures are ways of organizing and storing data in a computer so that it can be accessed and used efficiently.

• There are two main types of data structures: primitive and non-primitive

• Primitive data structures include integers, floats, characters, and booleans

• Non-primitive data structures include arrays, linked lists, stacks, queues, trees, and graphs

• Each data structure has its own advantages and disadvantages depending on the use case

64bit and 32bit refer to the size of data that a processor can handle.

• 64bit processors can handle larger amounts of memory and perform faster than 32bit processors.

• 64bit processors are more efficient in handling complex calculations and running multiple applications simultaneously.

• 32bit processors are limited to 4GB of RAM and can only handle 32bit software.

• Most modern computers and operating systems are 64bit.

• Examples of 64bit processors include Intel Core i5 and i7, AMD Ryz...read more

Control structure refers to the way a program is organized and executed based on certain conditions.

• Control structures are used to control the flow of a program.

• They include if-else statements, loops, and switch statements.

• If-else statements allow for conditional execution of code.

• Loops allow for repeated execution of code.

• Switch statements allow for multiple possible outcomes based on a single variable.

• Proper use of control structures can improve program efficiency and reada...read more

While loop executes only if the condition is true, do while loop executes at least once before checking the condition.

• While loop checks the condition first, then executes the code block

• Do while loop executes the code block first, then checks the condition

• While loop may not execute at all if the condition is false initially

• Do while loop always executes at least once

• While loop is a pre-test loop, do while loop is a post-test loop

Interview questions for Software Engineer on OOPs concepts, list and tuples, and sorting strings.

• OOPs concepts include inheritance, polymorphism, encapsulation, and abstraction.

• Lists and tuples are data structures in Python. Lists are mutable while tuples are immutable.

• To sort a string in Python, use the sorted() function or the sort() method.

OOPs concepts are the fundamental principles of object-oriented programming.

• Abstraction: Hiding implementation details and showing only necessary information.

• Encapsulation: Binding data and functions together in a single unit.

• Inheritance: Acquiring properties and behavior of a parent class by a child class.

• Polymorphism: Ability of an object to take many forms or have multiple behaviors.

• Association: Relationship between two objects.

• Aggregation: A special form of association wh...read more

Linked list is a linear data structure. DFS and BFS are graph traversal algorithms.

• Linked list is a collection of nodes where each node points to the next node.

• DFS (Depth First Search) is a traversal algorithm that explores as far as possible along each branch before backtracking.

• BFS (Breadth First Search) is a traversal algorithm that explores all the vertices of a graph in breadth-first order.

• Example of linked list: 1->2->3->4->5

• Example of DFS: starting from node A, explore...read more

Singleton class is a class that can have only one instance and provides a global point of access to it.

• Singleton class is used when we need to ensure that only one instance of a class is created throughout the application.

• It is implemented by making the constructor private and providing a static method to get the instance of the class.

• Example: java.lang.Runtime is a singleton class that provides access to the runtime environment of the current Java application.

• Singleton patte...read more

A network is a group of interconnected devices that can communicate and share resources.

• A network can be wired or wireless.

• Devices on a network can share files, printers, and internet access.

• Networks can be local (LAN) or wide area (WAN).

• Examples of networks include the internet, home Wi-Fi, and corporate intranets.

Array is a collection of elements of same data type. Linked list is a data structure where each element points to the next one.

• Arrays have fixed size, linked lists can grow dynamically

• Arrays have constant time access, linked lists have linear time access

• Arrays are stored in contiguous memory, linked lists are stored in non-contiguous memory

• Example of array: int[] arr = {1, 2, 3, 4, 5}

• Example of linked list: Node head = new Node(1); head.next = new Node(2);

To make a class immutable in Java, we need to follow certain rules.

• Make the class final so that it cannot be extended

• Make all the fields private and final

• Do not provide any setter methods

• If the class has mutable fields, return a copy of the field instead of the original in getter methods

• Ensure that any mutable objects passed to the constructor are not modified outside the class

• Override equals() and hashCode() methods to ensure that objects can be compared properly

Encapsulation is the process of hiding implementation details and providing a public interface for accessing the functionality.

• Encapsulation helps in achieving data abstraction and information hiding

• It prevents unauthorized access to the internal details of an object

• It allows for easy modification of implementation without affecting the external code

• Example: A class with private variables and public methods

• Example: A bank account class with methods for deposit and withdraw, b...read more

Convert nested array to flat array using custom method

• Create a recursive function to flatten the nested array

• Use Array.isArray() to check if an element is an array

• Concatenate arrays using Array.concat() method

An operating system is a software that manages computer hardware and software resources.

• It acts as an interface between the user and the computer hardware.

• It provides services to applications and manages system resources.

• Examples include Windows, macOS, Linux, Android, iOS.

• It controls the allocation of memory, processing power, and input/output devices.

• It provides security and protection to the system and user data.

Different types of testing include unit, integration, system, acceptance, and regression testing. Testing tools include Selenium, JUnit, and TestNG.

• Unit testing: testing individual units or components of code

• Integration testing: testing how different units or components work together

• System testing: testing the entire system as a whole

• Acceptance testing: testing to ensure the system meets the requirements of the stakeholders

• Regression testing: testing to ensure changes to the ...read more

DBMS is a software to manage databases while RDBMS is a type of DBMS that uses a relational model.

• DBMS stands for Database Management System while RDBMS stands for Relational Database Management System.

• DBMS can manage any type of database while RDBMS uses a relational model to manage data.

• DBMS does not enforce any specific data model while RDBMS enforces a tabular data model.

• Examples of DBMS include MongoDB and Cassandra while examples of RDBMS include MySQL and Oracle.

There are three types of loops in programming.

• The three types of loops are: for loop, while loop, and do-while loop.

• For loop is used when the number of iterations is known beforehand.

• While loop is used when the number of iterations is not known beforehand.

• Do-while loop is similar to while loop, but it executes at least once before checking the condition.

Optimize O(n2) program to O(log n)

• Use binary search instead of linear search

• Divide and conquer approach can be used

• Implement efficient data structures like heap, AVL tree, etc.

• Reduce unnecessary iterations and comparisons

• Use memoization to avoid redundant calculations

Remove unwanted spaces from a given string

• Use string manipulation functions to remove extra spaces

• Iterate through the string and remove any consecutive spaces

• Trim the string to remove leading and trailing spaces

Types of network include LAN, WAN, MAN, WLAN, VPN, PAN, SAN, CAN, and GAN.

• LAN (Local Area Network) connects devices within a small area

• WAN (Wide Area Network) connects devices across a large geographical area

• MAN (Metropolitan Area Network) connects devices within a city or metropolitan area

• WLAN (Wireless Local Area Network) uses wireless technology to connect devices within a small area

• VPN (Virtual Private Network) allows secure remote access to a private network

• PAN (Personal...read more

A pointer to pointer is a variable that stores the memory address of another pointer.

• It is used to store the address of a pointer variable.

• It allows indirect access to a memory location.

• Commonly used in dynamic memory allocation and multi-dimensional arrays.

Inheritance is a mechanism in object-oriented programming where a class inherits properties and behaviors from another class.

• Inheritance allows code reuse and promotes code organization.

• There are different types of inheritance: single, multiple, multilevel, hierarchical, and hybrid.

• Single inheritance involves a class inheriting from a single base class.

• Multiple inheritance involves a class inheriting from multiple base classes.

• Multilevel inheritance involves a class inheritin...read more

The choice of compiler in C depends on the platform and the specific needs of the project.

• Different platforms may have different default compilers, such as GCC on Linux and Clang on macOS.

• Some projects may require a specific compiler for compatibility or performance reasons.

• C compilers include GCC, Clang, Microsoft Visual C++, and Intel C++ Compiler, among others.

Thread is a lightweight process that can run concurrently with other threads in a program.

• There are two types of threads: user-level threads and kernel-level threads.

• User-level threads are managed by the application and are faster to create and switch between, but can't take advantage of multiple processors.

• Kernel-level threads are managed by the operating system and can take advantage of multiple processors, but are slower to create and switch between.

• Examples of thread libr...read more

Polymorphism is the ability of an object to take on many forms. It has two types: compile-time and runtime polymorphism.

• Compile-time polymorphism is achieved through function overloading and operator overloading.

• Runtime polymorphism is achieved through virtual functions and function overriding.

• Polymorphism allows for code reusability and flexibility in object-oriented programming.

• Example of compile-time polymorphism: function overloading - multiple functions with the same nam...read more

A pointer is a variable that stores the memory address of another variable.

• Pointers are used to indirectly access and manipulate data in memory.

• They are commonly used in programming languages like C and C++.

• Example: int *ptr; // declares a pointer to an integer variable

Polymorphism is the ability of a function or method to behave differently based on the object it is acting upon.

• Polymorphism allows objects of different classes to be treated as objects of a common superclass.

• It enables a single interface to be used for different data types or classes.

• Examples include method overloading and method overriding in object-oriented programming.

Inheritance is a concept in object-oriented programming where a class inherits attributes and methods from another class.

• Allows a class to inherit attributes and methods from another class

• Promotes code reusability and reduces redundancy

• Creates a parent-child relationship between classes

Groupby is used to group data based on a specific column, while Orderby is used to sort data based on a specific column.

• Groupby is used to create groups of data based on a specific column.

• Orderby is used to sort data based on a specific column in ascending or descending order.

• Groupby is often used in combination with aggregate functions like sum, count, etc.

• Orderby can be used to sort data in ascending or descending order.

• Groupby is commonly used in SQL queries, while Orderby...read more

Delete removes specific rows from a table, truncate removes all rows, and drop removes the entire table.

• Delete is a DML operation, while truncate and drop are DDL operations.

• Delete can be rolled back, while truncate and drop cannot be rolled back.

• Delete operation maintains the transaction log, while truncate and drop do not.

• Delete operation is slower compared to truncate and drop.

• Example: DELETE FROM table_name WHERE condition;

• Example: TRUNCATE TABLE table_name;

• Example: DROP ...read more