200+ Junior Software Engineer Interview Questions and Answers

SEO is the process of optimizing a website to rank higher in search engine results. Code optimization involves improving website code for better performance.

• SEO involves keyword research, on-page optimization, link building, and content creation

• Code optimization includes minimizing file sizes, reducing HTTP requests, and using caching

• Both SEO and code optimization are important for improving website visibility and user experience

Mobile friendly design can be achieved by using responsive design, optimizing images and using appropriate font sizes.

• Use responsive design to ensure the website adapts to different screen sizes

• Optimize images to reduce load times and improve performance

• Use appropriate font sizes to ensure readability on smaller screens

A database is a collection of data that is organized in a way that allows for easy retrieval and manipulation. A phone is a device used for communication.

• A database is used to store and manage large amounts of data, such as customer information or financial records.

• Phones can be used for making calls, sending text messages, browsing the internet, and accessing various apps.

• Databases and phones can be used together, such as when a mobile app stores user data in a cloud-based d...read more

HTML is a markup language used for creating web pages, while responsive design ensures web pages adapt to different screen sizes.

• HTML stands for HyperText Markup Language and is used to structure content on web pages.

• Responsive design is a design approach that ensures web pages look good on all devices and screen sizes.

• Responsive design uses CSS media queries to adjust the layout based on the device's screen size.

• An example of responsive design is a website that rearranges it...read more

Empty interfaces in Go are used to define types that can hold values of any type.

• Empty interfaces are used when you want to create a function or data structure that can accept values of any type.

• They are commonly used in Go for functions like fmt.Print which can accept any type of value.

• Empty interfaces are also used in Go's reflection package to work with values of unknown types.

C++ offers high performance, low-level control, and a wide range of applications.

• C++ is faster than many other programming languages due to its low-level control.

• C++ is widely used in developing operating systems, game engines, and high-performance applications.

• C++ supports object-oriented programming, templates, and generic programming.

• C++ has a large community and a vast library of pre-built functions and classes.

• C++ is backward compatible with C, allowing for easy integrat...read more

Delete removes rows from a table, truncate removes all rows from a table, drop removes a table from the database.

• Delete is a DML command which removes specific rows from a table.

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

• Drop is a DDL command which removes an entire table from the database.

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

• Example: DELETE FROM table_name WHERE condition;

• Exampl...read more

OOPs concepts are the fundamental principles of Object-Oriented Programming.

• Abstraction

• Encapsulation

• Inheritance

• Polymorphism

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

• OOPs focuses on creating objects that interact with each other to solve problems.

• Key principles of OOPs include encapsulation, inheritance, polymorphism, and abstraction.

• Encapsulation involves bundling data and methods that operate on the data into a single unit.

• Inheritance allows a class to inherit prope...read more

I have a strong understanding of programming concepts and have experience with various programming languages.

• Proficient in languages such as Java, Python, and C++

• Familiar with data structures and algorithms

• Experience with software development practices like version control and testing

• Completed projects involving web development and mobile app development

Diamond problem in Java occurs when a class inherits from two classes that have a common ancestor, resulting in ambiguity.

• Occurs in multiple inheritance scenarios

• Can be resolved using interfaces or by using the 'super' keyword to specify which parent class method to call

Use OFFSET and FETCH clauses in SQL to paginate responses.

• Use OFFSET to skip a specified number of rows before returning the remaining rows.

• Use FETCH to limit the number of rows returned after the OFFSET clause.

• Example: SELECT * FROM table_name ORDER BY column_name OFFSET 10 ROWS FETCH NEXT 10 ROWS ONLY

A function in Oracle Database is a named PL/SQL block that can accept parameters and return a value.

• Functions can be used to perform calculations, manipulate data, or return specific values.

• They can be called from SQL queries or other PL/SQL blocks.

• Functions must return a single value of a specified data type.

SQL is a domain-specific language used for managing and manipulating relational databases.

• SQL stands for Structured Query Language

• It is used to communicate with databases to retrieve, insert, update, and delete data

• Common SQL commands include SELECT, INSERT, UPDATE, DELETE

• SQL can be used to create and modify database schemas

• Joins are used to combine data from multiple tables in SQL

Yes, Java is platform independent due to its ability to compile code into bytecode that can run on any platform with a Java Virtual Machine (JVM).

• Java code is compiled into bytecode, which can run on any platform with a JVM.

• The JVM acts as an intermediary between the Java code and the underlying platform.

• This allows Java programs to be written once and run on any platform without modification.

Session and cookie are used to store data in PHP. Session is stored on the server, while cookie is stored on the client's browser.

• Session data is stored on the server and is accessible across different pages of a website.

• Cookie data is stored on the client's browser and can be accessed by the server on subsequent requests.

• Sessions are more secure as the data is stored on the server and not exposed to the client.

• Cookies can be set with an expiration time, while sessions expire...read more

Object oriented programming is a programming paradigm based on the concept of objects, which can contain data and code.

• OOP focuses on creating objects that interact with each other to solve problems

• Encapsulation, inheritance, and polymorphism are key principles of OOP

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

SQL is a programming language used to manage and manipulate relational databases. DDL is a subset of SQL used to define database schema.

• SQL stands for Structured Query Language

• It is used to create, modify, and query databases

• DDL stands for Data Definition Language

• It is used to define the structure of the database

• DDL commands include CREATE, ALTER, and DROP

• Example: CREATE TABLE students (id INT, name VARCHAR(50), age INT)

• Example: ALTER TABLE students ADD COLUMN email VARCHAR(5...read more

A program to find the addition of two numbers

• Declare two variables to store the numbers

• Take input from user or use predefined values

• Add the two numbers together

• Print the result

Program to check if a number is prime or not

• A prime number is only divisible by 1 and itself

• Start checking from 2 up to the square root of the number

• If the number is divisible by any number in the range, it's not prime

Joins in SQL are used to combine data from two or more tables based on a related column.

• Joins are used to retrieve data from multiple tables in a single query

• There are different types of joins such as inner join, left join, right join, and full outer join

• The join condition is specified using the ON keyword followed by the column(s) to join on

• Example: SELECT * FROM table1 INNER JOIN table2 ON table1.column = table2.column

Transformations are changes made to data to convert it from one form to another.

• Transformations are used in data processing and analysis.

• They can involve changing the format, structure, or content of data.

• Examples include converting data from one file type to another, normalizing data, and aggregating data.

• Transformations can be performed using programming languages, tools, or software.

• They are important for data integration, data cleaning, and data analysis.

Workflow monitors are tools used to track and manage the progress of tasks in a workflow.

• Workflow monitors provide real-time visibility into the status of tasks in a workflow.

• They can be used to identify bottlenecks and optimize workflow efficiency.

• Examples of workflow monitors include Apache Airflow, Jenkins, and AWS Step Functions.

A data warehouse is a large, centralized repository of data that is used for analysis and reporting.

• Data is extracted from various sources and transformed into a common format

• Data is organized into dimensions and facts for efficient querying

• Used for business intelligence and decision-making

• Examples include Amazon Redshift, Microsoft Azure Synapse Analytics

I am open to discussing a fair and competitive salary based on my skills and experience.

• I am looking for a salary that is commensurate with my skills and experience

• I am open to discussing the salary range for this position

• I am looking for a fair and competitive salary package

• I am willing to negotiate based on the company's compensation structure

Explicit intents specify the component to start by name. Implicit intents specify the action to perform.

• Explicit intents are used to start a specific component in the app by providing the component name.

• Implicit intents are used to request an action from another app without specifying the component name.

• Explicit intents are used when the target component is known, while implicit intents are used when the system should find the appropriate component.

• Example of explicit intent:...read more

Data cleaning is the process of identifying and correcting errors or inconsistencies in data to improve its quality.

• Removing duplicate entries

• Correcting spelling mistakes

• Handling missing values

• Standardizing data formats

• Identifying and removing outliers

String reverse and factorial programs in array of strings.

• For string reverse program, iterate through the string from end to beginning and append each character to a new string.

• For factorial program, use a loop to multiply numbers from 1 to n.

• Example for string reverse: Input 'hello' -> Output 'olleh'

• Example for factorial: Input 5 -> Output 120 (5*4*3*2*1)

I am aware of Git, SVN, Mercurial, and CVS.

• Git is the most popular and widely used version control system.

• SVN is a centralized version control system.

• Mercurial is similar to Git but with a simpler design.

• CVS is an older version control system that is not commonly used anymore.

TCL is not related to SQL. It stands for Tool Command Language and is used for scripting and automation.

• TCL is a scripting language used for automation and testing

• It is not related to SQL, which is a language used for managing relational databases

• TCL can be used to write scripts for various applications, including database management systems

• Example: TCL can be used to automate tasks in Oracle database management system

Code to reverse a number in JavaScript

• Convert the number to a string to easily manipulate each digit

• Use array methods like split, reverse, and join to reverse the number

• Convert the reversed string back to a number before returning

Add two arrays element-wise and reverse the resulting array of strings.

• Iterate through both arrays and add corresponding elements together.

• Reverse the resulting array of strings.

• Handle edge cases like arrays of different lengths.

• Example: ['1', '2', '3'] + ['4', '5', '6'] = ['5', '7', '9'] -> reverse -> ['9', '7', '5']

String methods are used to manipulate and work with strings in programming languages.

• toUpperCase(): Converts a string to uppercase

• toLowerCase(): Converts a string to lowercase

• charAt(index): Returns the character at the specified index

• indexOf(substring): Returns the index of the first occurrence of a substring

• split(delimiter): Splits a string into an array of substrings based on a delimiter

Temp table and magic table are used in SQL for temporary storage and tracking changes respectively.

• Temp table is used to store intermediate results during a query execution.

• Magic table is used to track changes made to a table during an INSERT, UPDATE or DELETE operation.

• Temp table is created using CREATE TABLE statement with # or ## prefix.

• Magic table is accessed using the special INSERTED and DELETED tables.

• Temp table is dropped automatically at the end of a session or trans...read more

Access modifiers are keywords in object-oriented programming languages that set the accessibility of classes, methods, and other members.

• There are four access modifiers in Java: public, private, protected, and default

• Public members are accessible from anywhere in the program

• Private members are only accessible within the same class

• Protected members are accessible within the same class and its subclasses

• Default members are accessible within the same package

• Access modifiers help...read more

Error handling is the process of identifying, catching, and resolving errors in software programs.

• Errors can occur due to various reasons such as incorrect input, network issues, hardware failure, etc.

• Error handling involves using try-catch blocks, exception handling, and logging to handle errors.

• Proper error handling improves the reliability and usability of software programs.

• Examples of error handling include displaying error messages to users, retrying failed operations, a...read more

Goroutines are lightweight threads managed by Go runtime, while channels are used for communication between Goroutines.

• Goroutines are functions that run concurrently with other functions. They are created using the 'go' keyword.

• Channels are used to send and receive data between Goroutines. They are typed and can be either buffered or unbuffered.

• Channels can be created using the 'make' function, and data can be sent using the '<-' operator.

• Example: go func() { ch <- value }() ...read more

My expected CTC is based on industry standards and my experience level.

• Research industry standards for Junior Software Engineer salaries

• Consider my level of experience and skills

• Factor in location and cost of living

• Provide a range rather than a specific number (e.g. $50,000 - $60,000)

Find duplicates in a string array

• Iterate through the array and store each element in a hash set

• If an element is already in the hash set, it is a duplicate

Hoisting is a JavaScript mechanism where variable and function declarations are moved to the top of their containing scope during compilation.

• Variable declarations are hoisted to the top of their scope, but not their initializations.

• Function declarations are fully hoisted, including their definitions.

• Hoisting can lead to unexpected behavior if not understood properly.

Push and pop are operations used to add and remove elements from the end of an array.

• Push operation adds an element to the end of the array.

• Pop operation removes and returns the last element of the array.

• Example: array.push('element') adds 'element' to the end of the array.

• Example: array.pop() removes and returns the last element of the array.

Tableau is a data visualization tool used for creating interactive dashboards and reports.

• Tableau allows users to connect to various data sources and create visualizations using drag-and-drop functionality.

• It offers a wide range of chart types, including bar charts, line charts, scatter plots, and maps.

• Tableau also has features for data blending, filtering, and forecasting.

• It is commonly used in business intelligence, data analytics, and data science.

• Examples of companies usi...read more

Stateful widgets maintain state that can change over time, while stateless widgets do not.

• Stateful widgets have a mutable state that can be changed during the lifetime of the widget.

• Stateless widgets do not have any internal state and are immutable once built.

• Stateful widgets are useful for components that need to update their state dynamically, like forms or animations.

• Stateless widgets are more efficient as they do not need to manage state changes.

• Example: A counter widget ...read more

Linux file system is a hierarchical structure for organizing and storing files on a Linux operating system.

• Linux file system follows a tree-like structure with a root directory (/) at the top.

• Directories are used to organize files and other directories.

• Files are stored within directories and can be accessed using their path.

• Inodes are data structures that store metadata about files, such as permissions, ownership, and file type.

• File systems like ext4, XFS, and Btrfs are commo...read more

Projects are practical applications of skills and knowledge to solve real-world problems or create new products.

• Projects involve setting goals, planning tasks, and executing them within a specified timeline.

• They often require collaboration with team members and stakeholders.

• Projects can range from developing software applications to conducting research studies.

• Examples: Building a website for a client, creating a mobile app, implementing a new database system.

Computer programming is the process of designing and building instructions for a computer to execute.

• Computer programming involves writing code in programming languages such as Java, Python, C++, etc.

• Programmers use algorithms and data structures to solve problems and create software applications.

• Debugging and testing are important parts of programming to ensure the code works correctly.

• Examples of computer programming tasks include developing websites, mobile apps, and video...read more

An embedded system is a specialized computer system designed to perform specific tasks within a larger system.

• Embedded systems are often found in everyday devices such as smartphones, cars, and household appliances.

• They are typically designed to be low-cost, low-power, and reliable.

• Embedded systems can be programmed using a variety of languages such as C, C++, and assembly language.

• They often have real-time operating systems to ensure timely responses to events.

• Examples of em...read more