90+ Software Development Engineer 1 Interview Questions and Answers

Design a CLI-based polling system for users and administrators to manage and participate in polls.

• Admin can create a poll with a question and multiple options.

• Admin can delete a poll by its unique ID.

• Admin can update poll questions and options as needed.

• Users can vote only once per poll, tracked by user ID.

• Poll results can be displayed showing votes per option and user voting history.

Design a system for making table reservations at a restaurant.

• Create a user-friendly interface for customers to make reservations

• Allow customers to select date, time, and party size

• Provide real-time updates on table availability

• Integrate with the restaurant's seating chart and reservation system

• Send confirmation emails or texts to customers

• Allow customers to modify or cancel reservations

• Provide analytics for the restaurant to track reservations and customer behavior

Yes, I have hands-on experience developing a to-do application using React.

• Developed a simple to-do application using React

• Implemented features such as adding tasks, marking tasks as completed, and deleting tasks

• Utilized React state management and component lifecycle methods

I have experience in Artificial Intelligence, Machine Learning, and Cybersecurity.

• Artificial Intelligence: Familiar with neural networks, natural language processing, and computer vision.

• Machine Learning: Proficient in regression, classification, clustering algorithms, and model evaluation techniques.

• Cybersecurity: Knowledge of encryption, network security, and vulnerability assessment.

To find binary tree from preorder and postorder, use recursion and divide the arrays into left and right subtrees.

• Create a binary tree node using the first element of preorder array

• Find the root node's index in postorder array

• Divide the arrays into left and right subtrees recursively

To create a Spring Boot application, you can use Spring Initializr to generate a project with necessary dependencies and configurations.

• Go to https://start.spring.io/

• Select the project metadata like group, artifact, dependencies, etc.

• Click on 'Generate' to download the project zip file.

• Extract the zip file and import the project into your IDE.

• Start coding your Spring Boot application.

Spring Boot dependency management is a feature that simplifies managing dependencies in a Spring Boot project.

• Spring Boot uses Maven or Gradle for dependency management

• Dependencies are declared in the pom.xml file for Maven or build.gradle file for Gradle

• Spring Boot provides a 'starter' dependencies that include commonly used libraries and frameworks

• Version conflicts are resolved automatically by Spring Boot

Design a Flutter app with BLoC for state management and network operations.

• Use Flutter's MaterialApp for UI structure.

• Implement BLoC pattern for state management: Create a BLoC class to handle business logic.

• Use http package for network operations: Fetch data from an API and parse JSON.

• Example: Create a UserBloc to manage user data fetching and state.

• Utilize StreamBuilder to listen to BLoC state changes and update UI accordingly.

Count the number of islands in a 2D grid of 1s and 0s.

• An island is a group of connected 1s (horizontally or vertically).

• Use DFS or BFS to traverse the grid and mark visited cells.

• Count the number of times you start a traversal from an unvisited 1.

APIs use various data structures like JSON and XML for GET and POST requests to exchange data between client and server.

• JSON (JavaScript Object Notation): Lightweight data interchange format, easy to read and write. Example: {"name": "John", "age": 30}.

• XML (eXtensible Markup Language): Markup language that defines rules for encoding documents. Example: <person><name>John</name><age>30</age></person>.

• Form Data: Used in POST requests to send data as key-value pairs. Example: na...read more

Default method in Java 8 allows interfaces to have method implementations.

• Introduced in Java 8 to provide backward compatibility for interfaces

• Default methods can be overridden by implementing classes

• Used to add new methods to interfaces without breaking existing implementations

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

• 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: Inheritance allows a child class to override a method from its parent class, providing different functionality.

To find a bug in a React problem

• Check the console for any error messages

• Use React Developer Tools to inspect the component tree and state

• Check if the props and state are being updated correctly

• Check if the lifecycle methods are being called in the correct order

• Check if the event handlers are bound correctly

• Check if the JSX syntax is correct

The request-response cycle in DRF involves processing client requests and returning appropriate responses through views and serializers.

• 1. Client sends an HTTP request to the server, typically using RESTful methods like GET, POST, PUT, DELETE.

• 2. Django's URL dispatcher maps the request to a specific view based on the URL patterns defined in the application.

• 3. The view processes the request, often interacting with models to retrieve or manipulate data.

• 4. Serializers are used t...read more

Indexing in NoSQL is a technique used to optimize query performance by creating data structures that allow for faster data retrieval.

• Indexes in NoSQL databases are similar to indexes in relational databases, but they are typically more flexible and can be created on any field in a document.

• By creating indexes on specific fields, queries can quickly locate the desired data without having to scan through the entire database.

• Indexes can be created as single-field indexes or comp...read more

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 but not their initializations.

• Function declarations are fully hoisted, including their definitions.

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

Implement a simple CRUD API using GraphQL with search and sort functionalities.

• Define GraphQL schema with types for data entities, e.g., 'User' type with fields like 'id', 'name', 'email'.

• Implement resolvers for CRUD operations: createUser, getUser, updateUser, deleteUser.

• Use arguments in queries for search functionality, e.g., 'users(name: String)': to filter users by name.

• Implement sorting by adding an argument to queries, e.g., 'users(sortBy: String)': to sort users by spe...read more

Closure is a function that has access to its parent scope even after the parent function has returned.

• Closure is used for data privacy and encapsulation.

• It allows functions to have private variables that cannot be accessed from outside the function.

• It can be used to create factory functions that generate new functions with specific behavior.

• It is also used in event handling and callbacks.

• Example: function outer() { let x = 10; function inner() { console.log(x); } return inner...read more

Find the lowest common ancestor (LCA) of two nodes in a binary tree efficiently.

• The LCA of two nodes is the deepest node that is an ancestor of both nodes.

• Use a recursive approach to traverse the tree and check for the presence of the nodes.

• If the current node matches either of the nodes, return it.

• If both nodes are found in the left and right subtrees, the current node is the LCA.

• Example: In a tree with nodes 3, 5, and 1, the LCA of 5 and 1 is 3.

This question tests your understanding of data structures and algorithms using a programming language of your choice.

• Understand the problem statement clearly before coding.

• Identify the appropriate data structures (e.g., arrays, linked lists).

• Consider time and space complexity for your solution.

• Write clean, modular code with functions for better readability.

• Test your solution with edge cases (e.g., empty arrays, large inputs).

Calculate the area under a graph using numerical integration.

• Use numerical integration methods like trapezoidal rule or Simpson's rule to approximate the area under the curve.

• Divide the graph into small segments and calculate the area of each segment, then sum them up to get the total area.

• Make sure to handle cases where the graph is below the x-axis by taking the absolute value of the function before calculating the area.

Design a shopping cart and find nearest palindrome number to a given number.

• Design a class for the shopping cart with methods like add item, remove item, calculate total price, etc.

• Implement a function to find the nearest palindrome number to a given number.

• You can iterate from the given number and check if each number is a palindrome until you find the nearest one.

Annotation used in Spring framework to indicate that a class is a RESTful controller

• Used in Spring framework to define RESTful web services

• Eliminates the need for annotating every method with @ResponseBody

• Combines @Controller and @ResponseBody annotations

Remove duplicates from a list

• Create a new empty list

• Loop through the original list

• If an element is not in the new list, add it

• Return the new list

Moodle database is a database system used by the Moodle learning management system to store and manage user data, course information, and other related data.

• Moodle database stores user profiles, course content, grades, and other information related to online learning.

• It uses a relational database management system like MySQL or PostgreSQL to store data.

• The database schema is designed to support the various features and functionalities of the Moodle platform.

• Queries can be run...read more

Callback hell is a situation where multiple nested callbacks make the code difficult to read and maintain.

• Use named functions instead of anonymous functions to make the code more readable.

• Use promises or async/await to handle asynchronous operations in a more organized way.

• Break down complex functions into smaller, reusable functions to avoid deep nesting.

• Use libraries like async.js or lodash to handle asynchronous operations more efficiently.

The Word Break problem checks if a string can be segmented into valid words from a given dictionary.

• Use dynamic programming to solve the problem efficiently.

• Create a boolean array 'dp' where dp[i] indicates if the substring s[0:i] can be segmented.

• Initialize dp[0] to true, as an empty string can always be segmented.

• Iterate through the string and check all possible substrings against the dictionary.

• Example: For s = 'leetcode' and dict = ['leet', 'code'], dp[8] will be true.