Junior Software Developer
50+ Junior Software Developer Interview Questions and Answers for Freshers
Q1. Given n coins for two players playing a game. Each player picks coins from the given n coins in such a way that he can pick 1 to 5 coins in one turn and the game continues for both the players. The player who p...
read moreThe 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.
Q2. Did You Know what is golang and where did You uses that? Why You want to switch the job? what is your acceptation about salary? Are you comfortable to work in this location?
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
Q3. Recursive code to reverse a linked list(Handle all corner cases: when list has no nodes or contains a single node)
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
Q4. Write a function to check whether a binary tree is a sub-tree of another binary tree (Check for all corner cases)
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
Q5. What is the difference between a constructor and a method?
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
Q6. what is Binary Serch Tree and its Time Complexity.
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
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Q7. Given a sorted array of 0’s and 1’s. Find out the no. of 0’s in it. Write recursive, iterative versions of the code and check for all test cases
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.
Q8. Given two numbers represented by two linked lists, write a function that returns sum list. The sum list is linked list representation of addition of two input numbers
Function to add two numbers represented by linked lists and return the sum list.
Traverse both linked lists and add corresponding nodes, keeping track of carry
Create a new linked list to store the sum
Handle cases where linked lists are of different lengths
Handle cases where the sum has an extra digit due to carry
Return the sum linked list
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Q9. Difference between array and linked list ? Arraylist and LinkedList in collection framework
Array is a fixed-size data structure while linked list is a dynamic data structure. ArrayList and LinkedList are implementations of List interface in Java.
Array is a contiguous block of memory with fixed size, while linked list is a collection of nodes where each node points to the next node.
ArrayList in Java is implemented using an array, which can dynamically resize itself. LinkedList is implemented using nodes with references to the next and previous nodes.
Arrays are faste...read more
Q10. What is Super ? Why Java is platform Independent? What is Multiple Inheritance? What is diamond Problem? What is Normalization? Sql Where condition Query? and many more..
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
Q11. Given a number n, find the number just greater than n using same digits as that of n
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
Q12. Given a string. Write a program to form a string with first character of all words
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
Q13. Spring boot: Put vs Post method, how will you create rest apis, how will you validate the input,
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
Q14. What is the difference between a library and a framework?
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
Q15. What do you know about software development life-cycle.
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
Q16. OOPs in detail with Inheritance, polymorphism, interface and abstract class ?
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
Q17. Tell me the what is abstraction and inheritance and encapsulation, polymorphism. (oops)
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
Q18. How do you check for the JWT in the postman?
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.
Q19. How will you hide the network data in inspection?
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
Q20. difference between interface and abstract class
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
Q21. Explain Quick sort , Merge Sort algorithm
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]
Q22. Write down the linked list implementation code .
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
Q23. What is OOPs and it's pillars ?
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
Q24. Python Data structures(difference between list and tuple)
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)
Q25. Find a pair with maximum product in array of integers
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)
Q26. What is the uses of 0ython
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
Q27. SUM OF PRIME NUMBERS
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
Q28. In the future, will Java technology be utilized here?
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.
Q29. Difference between abstract and interface
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
Q30. What programming languages do you know?
I am proficient in Java, Python, and JavaScript.
Java
Python
JavaScript
Q31. Difference between Truncate, Delete and Drop
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
Q32. HashMap vs ArrayList, oops, a program in stream,
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.
Q33. what is polymorphism
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.
Q34. How to write suitable code structure
Suitable code structure involves proper organization, readability, and maintainability.
Use consistent naming conventions for variables, functions, and classes.
Break down complex tasks into smaller, more manageable functions.
Follow the SOLID principles to ensure code is modular and easy to modify.
Use comments and documentation to explain the purpose and functionality of code.
Consider the needs of future developers who may need to work with the code.
Use version control to track...read more
Q35. What's HTM? Have uh learned it
HTML stands for Hypertext Markup Language. It is the standard markup language for creating web pages and web applications.
HTML is used to structure content on the web.
It consists of elements enclosed in tags, such as <p> for paragraphs.
Attributes can be added to elements to provide additional information.
HTML5 is the latest version of HTML, introducing new features like <video> and <canvas>.
CSS is often used in conjunction with HTML to style web pages.
Q36. What is java why we need choose software
Java is a popular programming language used for developing software applications.
Java is platform-independent, meaning it can run on any operating system.
It has a large standard library with built-in functions and classes for common tasks.
Java supports object-oriented programming, making it easier to organize and reuse code.
It provides automatic memory management through garbage collection.
Java is widely used in enterprise applications, web development, Android app developmen...read more
Q37. java code on HashMap().
HashMap is a data structure in Java that stores key-value pairs.
HashMap is part of the Java Collections framework.
Keys in a HashMap must be unique.
Values in a HashMap can be duplicated.
Example: HashMap
map = new HashMap<>(); Example: map.put("John", 25);
Q38. Try catch block and garbage collection
Try catch block is used for error handling, while garbage collection is automatic memory management in programming.
Try catch block is used to handle exceptions in code and prevent crashes.
Garbage collection automatically manages memory by deallocating unused objects.
Example: try { // code that may throw an exception } catch (Exception e) { // handle the exception }
Example: Garbage collection in Java automatically deallocates memory for objects no longer in use.
Q39. write a query to slect the 1 st highest salry
Use a subquery to select the highest salary from the table
Use a subquery to find the maximum salary in the table
Select all columns from the table where the salary matches the maximum salary found in the subquery
Q40. What Is primary key
Primary key is a unique identifier for a record in a database table.
Primary key ensures data integrity and helps in faster data retrieval.
It cannot have null or duplicate values.
Examples of primary keys are social security number, email address, etc.
Q41. What the components of react?
React is a JavaScript library for building user interfaces.
Components are the building blocks of a React application
Components can be class components or functional components
Components can have state and props
Components can be reused throughout the application
Q42. Difference between Sets, Lists, Tuples
Sets, Lists, and Tuples are all data structures in Python with different characteristics and use cases.
Sets are unordered collections of unique elements. Example: {1, 2, 3}
Lists are ordered collections of elements that can be modified. Example: [1, 2, 3]
Tuples are ordered collections of elements that cannot be modified. Example: (1, 2, 3)
Q43. Coding round - palindrome number
Check if a number is a palindrome or not
Convert the number to a string
Reverse the string and compare with the original string
If they are the same, the number is a palindrome
Q44. Encapsulation with real life examples
Encapsulation is the concept of bundling data and methods that operate on the data into a single unit.
Encapsulation helps in hiding the internal state of an object and only exposing necessary functionalities.
It allows for better control over the data by preventing direct access from outside the class.
Example: A car object encapsulates its properties like speed, fuel level, and methods like start, stop, accelerate.
Example: A bank account object encapsulates its balance, accoun...read more
Q45. Ready to shift in gandhinagar
Yes, I am ready to shift to Gandhinagar.
I am excited about the opportunity to work in Gandhinagar.
I have researched the area and am comfortable with the location.
I am willing to relocate and make the necessary arrangements.
I am open to exploring the city and its culture.
Q46. what is javascript
JavaScript is a high-level, interpreted programming language used for creating interactive websites and web applications.
JavaScript is commonly used for client-side web development.
It can also be used for server-side development with Node.js.
JavaScript allows for dynamic content, interactivity, and animations on websites.
Examples include form validation, interactive maps, and dynamic page content.
Q47. why weuse react js
React JS is a popular JavaScript library for building user interfaces.
Allows for reusable components
Virtual DOM for efficient updates
Declarative syntax for easier development
Q48. What is a oops?
OOPs stands for Object-Oriented Programming. It is a programming paradigm based on the concept of objects, which can contain data and code.
OOPs focuses on creating objects that interact with each other to solve problems
It involves concepts like inheritance, encapsulation, polymorphism, and abstraction
Examples of OOP languages include Java, C++, and Python
Q49. Explain break, pass, continue
break, pass, and continue are control flow statements used in programming to alter the flow of execution.
break: used to exit a loop or switch statement
pass: not a keyword in most programming languages, but can be used as a placeholder for future code
continue: used to skip the rest of the current iteration in a loop and start the next iteration
Q50. List and its methods/functions
List is a data structure in Python that stores a collection of items in a specific order.
Common methods/functions for lists in Python include append(), remove(), sort(), and index().
Lists can contain different data types, such as strings, integers, and even other lists.
Lists are mutable, meaning you can change the elements within a list after it has been created.
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