200+ Junior Software Developer Interview Questions and Answers

OOPs stands for Object-Oriented Programming and its pillars are Inheritance, Encapsulation, Abstraction, and Polymorphism.

• Inheritance allows a class to inherit properties and behavior from another class.

• Encapsulation restricts access to certain components within a class, protecting the data.

• Abstraction hides the complex implementation details and only shows the necessary features.

• Polymorphism allows objects to be treated as instances of their parent class, enabling flexibilit...read more

Spring Boot simplifies Java development with rapid setup, built-in features, and microservices support.

• Rapid Development: Spring Boot allows developers to create stand-alone applications quickly with minimal configuration.

• Convention over Configuration: It provides sensible defaults, reducing the need for extensive XML configuration.

• Embedded Servers: Spring Boot includes embedded servers like Tomcat and Jetty, enabling easy deployment and testing.

• Microservices Ready: It suppor...read more

Angular Life Cycle Hooks are methods that allow you to tap into the lifecycle of a component or directive.

• ngOnChanges - called when an input property changes

• ngOnInit - called once the component is initialized

• ngDoCheck - called during every change detection run

• ngAfterContentInit - called after content (ng-content) has been projected into the component

• ngAfterContentChecked - called after every check of the projected content

• ngAfterViewInit - called after the component's view has...read more

To find the mean of an array, add all the elements and divide by the number of elements.

• Add all the elements of the array

• Divide the sum by the number of elements

• Return the mean value

LINQ queries simplify data manipulation in .NET, allowing for concise and readable code to query collections and databases.

• Use LINQ to filter data: var results = data.Where(x => x.Age > 18);

• Project data into new forms: var names = data.Select(x => x.Name);

• Sort data easily: var sortedData = data.OrderBy(x => x.Name);

• Group data: var groupedData = data.GroupBy(x => x.Category);

• Join collections: var joinedData = data1.Join(data2, x => x.Id, y => y.Id, (x, y) => new { x, y });

I am interested in both front-end and back-end development.

• I enjoy creating user interfaces with HTML, CSS, and JavaScript.

• I also like working with databases and server-side languages like Python and PHP.

• I believe that having knowledge of both front-end and back-end development is important for creating well-rounded applications.

A DLL (Dynamic Link Library) is a file containing code and data that can be used by multiple programs at the same time. OOPs (Object-Oriented Programming) concepts include inheritance, polymorphism, encapsulation, and abstraction.

• DLL stands for Dynamic Link Library and contains code and data that can be used by multiple programs simultaneously

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

• Inheritance allows a class to inherit properties and beh...read more

The .NET application life cycle involves several stages from compilation to execution.

• Compilation of source code into MSIL (Microsoft Intermediate Language)

• Loading of MSIL into CLR (Common Language Runtime)

• Just-in-time (JIT) compilation of MSIL into machine code

• Execution of machine code by the operating system

• Garbage collection to free up memory used by the application

To find prime numbers between 1 and n, we can use algorithms like the Sieve of Eratosthenes for efficiency.

• A prime number is a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers.

• Examples of prime numbers: 2, 3, 5, 7, 11, 13, 17, 19.

• The Sieve of Eratosthenes is an efficient algorithm to find all primes up to a specified integer n.

• For n = 10, the prime numbers are: 2, 3, 5, 7.

• For n = 20, the prime numbers are: 2, 3, 5, 7, 11, 13, 17, ...read more

Lists are mutable, ordered collections of items, while tuples are immutable, ordered collections of items.

• Lists are denoted by square brackets [], while tuples are denoted by parentheses ().

• Lists can be modified after creation, while tuples cannot be modified.

• Lists are typically used for collections of similar items that may need to be changed, while tuples are used for fixed collections of items.

• Example: list_example = [1, 2, 3], tuple_example = (4, 5, 6)

Use array methods like sort() and find the middle element using Math.floor()

• Use array.sort() method to sort the array of strings alphabetically

• Use Math.floor() to find the middle element index in the sorted array

• Access the middle element using the index found

Used ACID properties in a banking application to ensure data consistency and reliability.

• Implemented transactions to ensure atomicity of operations

• Utilized isolation levels to prevent concurrent access issues

• Used locking mechanisms to maintain data consistency

• Ensured durability of data by committing changes to disk

Find a pair of integers in an array with the maximum product.

• Iterate through the array and keep track of the maximum and second maximum values.

• Consider negative numbers and zero.

• Time complexity: O(n)

I have knowledge in various technologies used in software development.

• Java

• Python

• C++

• HTML/CSS

• JavaScript

• SQL

• Git

• Linux

• Agile methodologies

Boxing is the process of converting a value type to a reference type, while unboxing is the opposite process.

• Boxing is done implicitly by the compiler when a value type is assigned to a reference type variable.

• Unboxing requires explicit casting to convert a reference type back to a value type.

• Example: int num = 10; object obj = num; // Boxing

• Example: int num2 = (int)obj; // Unboxing

Redux is a state management library for JavaScript applications.

• Redux helps manage the state of an application in a predictable way

• It provides a central store for all the application's state

• Actions are dispatched to update the store, and components can subscribe to changes in the store

• Redux can be used with React, Angular, and other JavaScript frameworks

A random condition to write javascript code.

• Use a conditional statement to check if a variable is equal to a certain value

• Create a function that generates a random number and use it in a conditional statement

• Use the Math.random() method to generate a random number and use it in a conditional statement

OOPs stands for Object-Oriented Programming. Its pillars are Inheritance, Encapsulation, Abstraction, and Polymorphism.

• Inheritance allows a class to inherit properties and behavior from another class. For example, a 'Car' class can inherit from a 'Vehicle' class.

• Encapsulation refers to the bundling of data and methods that operate on the data into a single unit. This helps in data hiding and access control.

• Abstraction focuses on hiding the complex implementation details and s...read more

Angular is a popular front-end framework for building dynamic web applications.

• Angular is a TypeScript-based open-source front-end web application framework.

• It allows developers to build single-page applications with dynamic content.

• Angular provides features like data binding, dependency injection, and routing.

• Examples of popular Angular applications include Gmail and Netflix.

CLI stands for Command Line Interface. It is a text-based interface used to interact with a computer system.

• CLI allows users to input commands to perform tasks on a computer system

• It is commonly used in operating systems like Unix, Linux, and Windows

• Examples of CLI commands include 'ls' to list files, 'cd' to change directories, and 'mkdir' to create a new directory

Python is a high-level programming language used for web development, data analysis, artificial intelligence, and more.

• Web development using frameworks like Django and Flask

• Data analysis and visualization using libraries like Pandas and Matplotlib

• Artificial intelligence and machine learning using libraries like TensorFlow and Scikit-learn

• Scripting and automation tasks

• Game development using Pygame

• Desktop application development using PyQt and Tkinter

Calculate the sum of prime numbers.

• Iterate through numbers and check if each number is prime

• If a number is prime, add it to the sum

• Return the sum of prime numbers

TempData stores data for a single request while Session stores data for multiple requests.

• TempData is used to store data temporarily for a single request.

• Session is used to store data for multiple requests.

• TempData is cleared after a single request while Session data persists until the session expires or is cleared.

• TempData is useful for passing data between actions while Session is useful for maintaining user-specific data across multiple requests.

super and this are used in object-oriented programming to refer to the parent class and current instance respectively.

• super is used to call a method or constructor from the parent class

• this is used to refer to the current instance of the class

• super() must be the first statement in a constructor

• this() can be used to call another constructor in the same class

Yes, Java technology is likely to be utilized in the future due to its popularity, versatility, and continuous updates.

• Java is a widely used programming language in various industries, including software development.

• Many companies rely on Java for their applications and systems, making it a valuable skill for developers.

• Java's strong community support and frequent updates ensure its relevance and longevity in the tech industry.

Abstract classes are classes that cannot be instantiated and can have both abstract and non-abstract methods. Interfaces are contracts that define the methods that a class must implement.

• Abstract classes can have constructors while interfaces cannot

• A class can implement multiple interfaces but can only inherit from one abstract class

• Abstract classes can have instance variables while interfaces cannot

• Interfaces can have default methods while abstract classes cannot

• An abstract ...read more

Event loop is a mechanism that allows JavaScript to perform non-blocking I/O operations.

• Event loop is a part of JavaScript runtime that continuously checks the call stack and the task queue.

• It executes the tasks in the task queue one by one, and once the task is completed, it moves to the next task in the queue.

• React is a JavaScript library for building user interfaces using a component-based architecture.

• React uses a virtual DOM to efficiently update the actual DOM.

• React all...read more

Arrow functions are a concise way to write functions in JavaScript.

• Arrow functions are written using the '=>' syntax.

• They do not have their own 'this' keyword, instead they inherit it from the parent scope.

• They are often used for short, one-line functions.

• Example: const add = (a, b) => a + b;

Async JavaScript allows for non-blocking code execution, improving performance by handling multiple tasks simultaneously.

• Async JavaScript uses Promises, async/await, and callbacks to handle asynchronous operations.

• It allows for tasks like fetching data from a server or updating the UI without blocking the main thread.

• Example: Using async/await to fetch data from an API asynchronously.

Comments in JavaScript are used to explain code and make it more readable.

• Single-line comments start with //

• Multi-line comments start with /* and end with */

• Comments should be concise and relevant to the code

• Avoid commenting obvious code

• Use comments to explain complex logic or algorithms

Abstract classes are classes that cannot be instantiated, while interfaces are a collection of abstract methods.

• Abstract classes can have both abstract and non-abstract methods, while interfaces can only have abstract methods.

• A class can only extend one abstract class, but can implement multiple interfaces.

• Abstract classes can have constructors, while interfaces cannot.

• An abstract class can provide default implementations for some methods, while interfaces cannot.

• Abstract cla...read more

Index is a pointer to a specific element in an array or database table.

• Indexes improve query performance by reducing the number of rows that need to be scanned.

• Types of indexes include clustered, non-clustered, unique, and composite indexes.

• Clustered indexes determine the physical order of data in a table, while non-clustered indexes create a separate structure.

• Unique indexes ensure that each value in the index column is unique, while composite indexes combine multiple column...read more

Paging is a memory management scheme that allows the operating system to use secondary storage as an extension of the computer's primary memory.

• Paging divides the physical memory into fixed-size blocks called pages.

• Virtual memory is divided into fixed-size blocks called frames.

• The operating system keeps track of the mapping between pages and frames using a page table.

• When a process requests data that is not in physical memory, a page fault occurs and the operating system swap...read more

Overloading allows multiple methods with the same name but different parameters; overriding redefines a method in a subclass.

• Overloading occurs within the same class.

• Example of overloading: 'int add(int a, int b)' and 'double add(double a, double b)'.

• Overriding occurs in a subclass, redefining a method from the superclass.

• Example of overriding: 'void display()' in a subclass that changes behavior from the superclass.

• Overloading is resolved at compile time (static binding), wh...read more

I am proficient in Java, Python, and JavaScript.

• Java

• Python

• JavaScript

A simple address book application with CRUD operations.

• Create a database to store contact information

• Implement a form to add new contacts

• Create a list view to display all contacts

• Add edit and delete functionality for each contact

• Use SQL queries to perform CRUD operations

Microcontrollers are small computers on a single integrated circuit used to control electronic devices.

• Microcontrollers are designed for specific tasks and are often used in embedded systems.

• They typically have on-board memory, input/output peripherals, and a central processing unit.

• Examples include Arduino, Raspberry Pi, and PIC microcontrollers.

Asynchronous and synchronous refer to different methods of executing code in relation to time.

• Synchronous code is executed in a sequential order, one task at a time.

• Asynchronous code allows multiple tasks to be executed concurrently, without waiting for each other to finish.

• Examples of synchronous operations include reading a file line by line, while examples of asynchronous operations include making API calls or handling user input in a web application.

Truncate removes all rows from a table, Delete removes specific rows, and Drop deletes the entire table structure.

• Truncate is a DDL command that removes all rows from a table but keeps the table structure intact.

• Delete is a DML command that removes specific rows based on a condition.

• Drop is a DDL command that deletes the entire table structure along with all its data.

• Truncate is faster than Delete as it does not log individual row deletions.

• Drop is irreversible and cannot be ...read more

HashMap is used for key-value pairs, ArrayList is used for dynamic arrays. Stream is used for processing collections.

• HashMap stores key-value pairs, allows fast retrieval based on keys.

• ArrayList stores elements in a dynamic array, allows fast access by index.

• Stream is used for processing collections in a functional style, supports operations like filter, map, reduce.

Different types of errors include syntax errors, runtime errors, and logical errors.

• Syntax errors: Errors in the code structure that prevent it from being compiled or executed.

• Runtime errors: Errors that occur during program execution, such as division by zero or accessing an out-of-bounds array element.

• Logical errors: Errors in the program's logic that result in incorrect output or behavior.

• Examples: Syntax error - missing semicolon at the end of a statement. Runtime error -...read more

Composition API is a new feature in Vue 3 that allows for better organization of code by grouping related logic together.

• Composition API allows for better reusability and organization of code compared to Options API.

• It encourages breaking down logic into composable functions that can be easily reused across components.

• Composition API provides better TypeScript support and allows for better separation of concerns.

• Example: Instead of using data, methods, computed properties, et...read more

CMOS stands for Complementary Metal-Oxide-Semiconductor. It is a type of technology used in electronic devices.

• CMOS is a type of semiconductor technology used in microprocessors, memory chips, and other electronic devices.

• It uses both p-type and n-type metal-oxide-semiconductor field-effect transistors (MOSFETs) to reduce power consumption and increase speed.

• CMOS is commonly used in digital circuits, such as in computers, smartphones, and cameras.

• Examples of CMOS-based device...read more

OOP stands for Object-Oriented Programming. It is a programming paradigm that uses objects to represent and manipulate data.

• OOP focuses on creating reusable code by organizing data and behavior into objects

• Objects have properties (attributes) and methods (functions) that can be accessed and modified

• Inheritance allows objects to inherit properties and methods from parent objects

• Polymorphism allows objects to take on multiple forms or behaviors

• Encapsulation hides the complexity...read more

Polymorphism is the ability of a single function or method to operate on different types of data.

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

• There are two types of polymorphism: compile-time (method overloading) and runtime (method overriding).

• Example: a superclass Animal with subclasses Dog and Cat. Both Dog and Cat can be treated as Animals.

I will use CSS to style HTML elements and create visually appealing web pages.

• Use CSS selectors to target specific HTML elements

• Apply CSS properties like color, font-size, and margin to style elements

• Utilize CSS frameworks like Bootstrap for responsive design

• Use CSS preprocessors like SASS for easier styling

Java is an object-oriented programming language while C is a procedural programming language.

• Java is platform-independent while C is platform-dependent.

• Java has automatic memory management while C requires manual memory management.

• Java has built-in support for multithreading while C requires external libraries for multithreading.

• Java has a larger standard library compared to C.

• Java is used for developing web applications, mobile applications, and enterprise software while C i...read more