60+ Junior Software Developer Interview Questions and Answers for Freshers

The player who picks the last coin loses the game.

• The game starts with n coins.

• Each player can pick 1 to 5 coins in one turn.

• The player who picks the last coin loses the game.

• Determine if the given n coins will result in a win or loss for the starting player.

Answering questions about golang, job switch, salary expectations, and location comfort.

• Golang is a programming language developed by Google, known for its simplicity and efficiency.

• I have used golang in my previous job to develop a microservices architecture for a web application.

• I am looking to switch jobs to gain new experiences, challenges, and opportunities for growth.

• My salary expectation is based on my skills, experience, and market standards.

• I am comfortable working i...read more

Reverse a linked list using recursion, handling all corner cases

• Create a recursive function that takes the head of the linked list as input

• Base case: if the head is null or the list contains only one node, return the head

• Recursively call the function with the next node as input and set its next pointer to the current node

• Set the current node's next pointer to null and return the new head

Write a function to check whether a binary tree is a sub-tree of another binary tree (Check for all corner cases)

• Create a function that traverses both trees and compares them

• Check if the root of the second tree matches any node in the first tree

• Handle cases where one or both trees are empty

• Handle cases where the trees have different structures

Constructor creates and initializes an object, while method performs an action on an object.

• Constructor has the same name as the class and is called when an object is created

• Method has a name that describes the action it performs on an object

• Constructor initializes the object's state, while method changes the object's state

• Constructor doesn't have a return type, while method can have a return type

• Example: public class Car { public Car() { ... } public void start() { ... } }

• In...read more

Count the number of 0's in a sorted array of 0's and 1's.

• Iterative solution: Traverse the array and count the number of 0's.

• Recursive solution: Divide the array into two halves and recursively count the number of 0's in each half.

• Binary search can also be used to find the first occurrence of 0 and then count the number of 0's after that index.

Binary Search Tree is a data structure where each node has at most two children, with left child smaller and right child larger. Time complexity is O(log n) for search, insert, and delete operations.

• Nodes have at most two children - left child is smaller, right child is larger

• Search, insert, and delete operations have time complexity of O(log n)

• Example: In a BST, if we search for a value, we can eliminate half of the remaining nodes at each step

A list of technical questions for a Junior Software Developer position.

• Super is a keyword in Java used to refer to the parent class.

• Java is platform independent due to its bytecode being able to run on any platform with a JVM.

• Multiple Inheritance is the ability for a class to inherit from multiple parent classes.

• The diamond problem occurs when a class inherits from two classes that have a common ancestor, causing ambiguity.

• Normalization is the process of organizing data in a ...read more

Given a number n, find the number just greater than n using same digits as that of n

• Convert the number to a string and sort the digits in ascending order

• Starting from the rightmost digit, find the first digit that is smaller than the digit to its right

• Swap this digit with the smallest digit to its right that is greater than it

• Sort the digits to the right of the swapped digit in ascending order

• Concatenate the digits to get the next greater number

Program to form a string with first character of all words in a given string.

• Split the string into an array of words

• Iterate through the array and extract the first character of each word

• Join the extracted characters to form the final string

In Spring Boot, PUT is used to update an existing resource, while POST is used to create a new resource. Input validation can be done using annotations like @Valid.

• Use PUT method to update an existing resource

• Use POST method to create a new resource

• Validate input using annotations like @Valid in Spring Boot

A library is a collection of functions or classes that can be called by an external program, while a framework is a set of libraries that provide a structure for building applications.

• Library is used by the developer to perform specific tasks, while a framework dictates the overall structure of the application.

• Libraries are more flexible and allow developers to pick and choose which components to use, while frameworks have a more rigid structure.

• Examples of libraries include ...read more

OOPs is a programming paradigm based on the concept of objects, with features like inheritance, polymorphism, interfaces, and abstract classes.

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

• Polymorphism allows objects of different classes to be treated as objects of a common superclass. For example, a 'Shape' superclass can have subclasses like 'Circle' and 'Square'.

• Interfaces def...read more

Database keys are essential for identifying and establishing relationships between records in a database.

• Primary Key: A unique identifier for a record in a table, e.g., 'user_id' in a 'users' table.

• Foreign Key: A field that links to the primary key of another table, e.g., 'user_id' in an 'orders' table referencing 'users'.

• Composite Key: A combination of two or more columns to uniquely identify a record, e.g., 'order_id' and 'product_id' together in an 'order_items' table.

• Uniq...read more

Software development life-cycle is a process used to design, develop, test, and deploy software applications.

• SDLC consists of several phases such as planning, analysis, design, implementation, testing, and maintenance.

• Each phase has its own set of activities and deliverables to ensure the successful completion of the project.

• SDLC models include Waterfall, Agile, Scrum, and DevOps, each with its own approach to software development.

• The goal of SDLC is to produce high-quality s...read more

Abstraction, inheritance, encapsulation, and polymorphism are the four pillars of object-oriented programming.

• Abstraction is the process of hiding complex implementation details and showing only the necessary information to the user.

• Inheritance is the mechanism of creating a new class from an existing class, inheriting all the properties and methods of the parent class.

• Encapsulation is the practice of keeping the data and methods that operate on the data together in a single ...read more

Interface defines only method signatures while abstract class can have method implementations.

• Interface cannot have method implementations, only method signatures

• Abstract class can have method implementations along with abstract methods

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

• Interfaces are used to achieve multiple inheritance in Java

• Abstract classes can have constructors while interfaces cannot

Use encryption to hide network data from inspection.

• Implement SSL/TLS to encrypt data transmitted over the network

• Use VPNs to create secure tunnels for data transmission

• Utilize firewalls to restrict access to network data

• Implement secure coding practices to prevent data leakage

• Use encryption algorithms like AES to protect sensitive data

To check for JWT in Postman, use the 'Authorization' tab and select 'Bearer Token' type.

• In Postman, go to the 'Authorization' tab of your request.

• Select 'Bearer Token' from the dropdown menu.

• Enter the JWT token in the provided field.

• Send the request to authenticate using the JWT.

Quick sort and Merge sort are popular sorting algorithms used to efficiently sort arrays of elements.

• Quick sort: Divide and conquer algorithm, picks a pivot element and partitions the array around the pivot. Recursively sorts subarrays.

• Merge sort: Divide and conquer algorithm, divides the array into two halves, recursively sorts the halves, and then merges them back together.

• Example: Quick sort - [3, 6, 8, 10, 1, 2, 1], Merge sort - [7, 2, 4, 1, 5, 3]

Implementation of a linked list in code format

• Define a Node class with data and next pointer

• Create LinkedList class with methods like insert, delete, search

• Handle edge cases like empty list, inserting at beginning/end

Inheritance allows a class to inherit properties and methods from another class, promoting code reusability and organization.

• Base Class: The class from which properties and methods are inherited is called the base class or parent class. Example: 'Animal' class.

• Derived Class: The class that inherits from the base class is called the derived class or child class. Example: 'Dog' class inheriting from 'Animal'.

• Code Reusability: Inheritance promotes code reuse by allowing derived ...read more

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

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)

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

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)

Find the length of the longest substring in a string without repeating characters using a sliding window approach.

• Use a sliding window technique with two pointers to track the current substring.

• Maintain a set to store characters in the current substring.

• Expand the right pointer to include new characters until a repeat is found.

• When a repeat is found, move the left pointer to shrink the window until the repeat is removed.

• Example: For 'abcabcbb', the longest substring is 'abc' ...read more