3500+ Senior Software Engineer Interview Questions and Answers

To prevent deadlocks in SQL transactions, use proper transaction management techniques.

• Use a consistent order for acquiring locks on resources to avoid circular dependencies.

• Keep transactions short and release locks as soon as they are no longer needed.

• Use lock timeouts to prevent transactions from waiting indefinitely.

• Implement deadlock detection and resolution mechanisms.

• Consider using higher isolation levels like Serializable to minimize concurrency issues.

React program to change div background color if both input boxes > 10

• Create a state for each input box

• Add onChange event to each input box to update state

• Use useEffect to check if both input values are greater than 10

• If true, update state to change div background color

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

• Event loop is a loop that constantly checks the message queue and executes the next message if there is any.

• Phases are the different stages of the event loop, such as timers, I/O callbacks, idle, and poll.

• Event loop is crucial for Node.js to handle multiple requests simultaneously without blocking the main thread.

• Example: setTimeout() function is added to the timer phase and executed after...read more

Maven is a build automation tool used primarily for Java projects. It manages dependencies and builds the project.

• Maven is based on the concept of POM (Project Object Model) which describes the project dependencies, build process, and other configurations.

• Maven has different cycles such as validate, compile, test, package, verify, install, and deploy.

• The validate cycle checks if the project is correct and all necessary information is available.

• The compile cycle compiles the s...read more

AI applications include natural language processing, image recognition, recommendation systems, and autonomous vehicles.

• Natural language processing for chatbots and virtual assistants

• Image recognition for facial recognition and object detection

• Recommendation systems for personalized content suggestions

• Autonomous vehicles for self-driving cars

XML databases are easy for processing XML data, while file systems are easy for processing files.

• XML databases are designed specifically for storing and querying XML data.

• They provide efficient indexing and querying capabilities for XML documents.

• Examples of XML databases include eXist-db, BaseX, and MarkLogic.

• File systems, on the other hand, are well-suited for storing and processing files of any type.

• They provide a hierarchical structure for organizing files and directories...read more

Use SQL queries with ORDER BY and LIMIT to find nth and 3rd highest record.

• Use ORDER BY column_name DESC to sort records in descending order

• Use LIMIT 1 OFFSET n-1 to get the nth highest record

• For 3rd highest record, use LIMIT 1 OFFSET 2

String Builder is not synchronized and faster, while String Buffer is synchronized and slower.

• String Builder is not thread-safe, while String Buffer is thread-safe.

• String Builder is faster due to lack of synchronization, while String Buffer is slower due to synchronization.

• String Builder is recommended for single-threaded operations, while String Buffer is recommended for multi-threaded operations.

There are two main types of memory in a computer system: stack memory and heap memory.

• Stack memory is used for static memory allocation and is managed by the compiler. It is typically faster but limited in size.

• Heap memory is used for dynamic memory allocation and is managed by the programmer. It is slower but has a larger size.

• Examples: C programming language uses stack memory for function calls and heap memory for dynamic memory allocation.

Throttling is a technique used to control the rate of requests sent to a server.

• Throttling helps prevent server overload by limiting the number of requests processed at a time.

• Implementing a throttle function involves setting a maximum request rate and delaying excess requests.

• Example: Implementing a throttle function in a web application to limit the number of API calls made to a third-party service.

• Example: Throttling the rate of data transfer in a network to prevent conges...read more

Use dynamic programming to find the longest palindromic substring in a given string.

• Iterate through the string and expand around each character to find palindromes.

• Store the length of the longest palindrome found so far.

• Return the substring based on the start and end indices of the longest palindrome.

CyclicBarrier allows a group of threads to wait at a barrier until all threads have reached it, while CountDownLatch allows one or more threads to wait until a set of operations being performed in other threads completes.

• CyclicBarrier is reusable, while CountDownLatch is not.

• CyclicBarrier allows all threads to wait for each other, while CountDownLatch allows one thread to wait for others.

• CyclicBarrier resets automatically after all threads have reached the barrier, while Coun...read more

JPARepository is a Spring Data interface for JPA-based repositories, while CRUDRepository is a generic interface for CRUD operations.

• JPARepository extends CRUDRepository and provides additional JPA-specific methods.

• CRUDRepository is a generic interface for CRUD operations on a repository.

• JPARepository is typically used for JPA-based repositories, while CRUDRepository can be used for any type of repository.

• JPARepository provides methods like findAll(), findById(), save(), dele...read more

A promise is a commitment to do something in the future, typically used for asynchronous operations in JavaScript.

• Promises are used to handle asynchronous operations in JavaScript.

• They represent a value that may be available now, in the future, or never.

• Promises have three states: pending, fulfilled, or rejected.

• Example: new Promise((resolve, reject) => { setTimeout(() => resolve('Done!'), 1000); });

The interview questions cover topics like Microservice Architecture, project explanation, array manipulation, Nth highest salary, and Java fundamentals.

• Microservice Architecture involves breaking down a large application into smaller, independent services that communicate with each other.

• Explain a project you worked on, highlighting the technologies used, challenges faced, and the outcome.

• Target Sum in array involves finding two numbers in an array that add up to a specific t...read more

Use memoization, virtual DOM, and shouldComponentUpdate to avoid unnecessary rerenders and improve performance.

• Implement memoization to store the result of expensive function calls and avoid recalculating them.

• Use virtual DOM to efficiently update only the parts of the UI that have changed.

• Override shouldComponentUpdate to prevent unnecessary rerenders by comparing current and next props/state.

A good microservice architecture is a design approach where an application is composed of small, independent services that communicate over well-defined APIs.

• Each microservice should have a single responsibility

• Services should be loosely coupled and independently deployable

• Use of containerization technologies like Docker for scalability and flexibility

• Implement fault tolerance and resilience in the architecture

• Use of API gateways for managing communication between services

Kafka is a distributed streaming platform used for building real-time data pipelines and streaming applications.

• Kafka is used for real-time data processing, messaging, and event streaming.

• It provides high-throughput, fault-tolerant, and scalable messaging system.

• Example use case: Implementing a real-time analytics dashboard for monitoring website traffic.

Interface is a contract with no implementation, while abstract class can have some implementation.

• Interface cannot have any implementation, only method signatures.

• Abstract class can have both abstract methods and concrete methods.

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

• Interfaces are used to achieve multiple inheritance in Java.

• Example: interface Animal { void eat(); } abstract class Mammal { void breathe() { System.out.println("...read more

I prioritize tasks based on urgency and importance, and use time management techniques to ensure efficient completion.

• Create a to-do list and prioritize tasks based on urgency and importance

• Break down larger tasks into smaller, manageable chunks

• Use time management techniques such as the Pomodoro technique to stay focused and efficient

• Regularly reassess priorities and adjust the to-do list as needed

• Communicate with team members and stakeholders to ensure alignment on prioritie...read more

Virtual functions are functions that can be overridden in derived classes. vTable is a lookup table used to resolve virtual function calls.

• Virtual functions allow polymorphism and dynamic binding

• vTable is a table of function pointers used to resolve virtual function calls

• vPtr is a pointer to the vTable of an object

• Smart pointers are objects that manage the lifetime of dynamically allocated memory

• Types of smart pointers include unique_ptr, shared_ptr, and weak_ptr

• Exception han...read more

Startup class is used to configure services and middleware for an application.

• Startup class is a part of ASP.NET Core framework.

• It is used to configure the application's request pipeline.

• It includes methods for configuring services, middleware, and the application's request handling pipeline.

• The ConfigureServices method is used to add services to the dependency injection container.

• The Configure method is used to add middleware components to the request pipeline.

• Startup class ...read more

Primary key can be created through programming by using SQL commands or ORM frameworks.

• Use SQL commands like CREATE TABLE to define primary key constraints

• Use ORM frameworks like Hibernate to define primary key annotations

• Primary key can be a single column or a combination of columns

• Primary key ensures uniqueness and helps in faster data retrieval

Design patterns are reusable solutions to common problems in software design.

• Design patterns help in creating flexible, maintainable, and scalable software systems.

• Some common design patterns include Singleton, Factory, Observer, and Strategy.

• Singleton pattern ensures a class has only one instance and provides a global point of access to it.

• Factory pattern creates objects without specifying the exact class of object that will be created.

• Observer pattern defines a one-to-many ...read more

Directives in Angular are markers on DOM elements that tell Angular to attach a specified behavior to that DOM element or transform it.

• Directives are used to create reusable components or add behavior to existing components.

• There are three types of directives in Angular: Component, Structural, and Attribute directives.

• Component directives are used to create custom components with their own templates and logic.

• Structural directives change the DOM layout by adding or removing e...read more

Selenium grid is a tool used for running Selenium tests on multiple machines in parallel.

• Selenium grid allows for distributed testing across multiple machines and browsers.

• It consists of a hub and nodes, where the hub acts as a central point to control the test execution and the nodes are the machines where the tests are run.

• Selenium grid helps to reduce the time required for running tests and increases the test coverage.

• Example: A test suite can be run on multiple browsers a...read more

IQueryable is for querying data from a source that implements IQueryable interface while IEnumerable is for iterating over a collection of data.

• IQueryable is used for deferred execution while IEnumerable is used for immediate execution.

• IQueryable is used for querying data from a remote data source while IEnumerable is used for querying data from an in-memory collection.

• IQueryable is more efficient for large datasets as it allows for server-side filtering, sorting, and paging....read more

Singleton design pattern ensures a class has only one instance and provides a global point of access to it.

• Create a private static instance of the class within the class itself.

• Provide a public static method to access the instance.

• Ensure the constructor of the class is private to prevent instantiation from outside the class.

• Example: Singleton pattern is commonly used in database connections to ensure only one connection is established.

Angular applications operate by following a specific lifecycle process.

• Angular application starts by bootstrapping the root module.

• Components are created and rendered based on the component tree.

• Data binding ensures synchronization between the model and view.

• Angular runs change detection to update the view when data changes.

• Services provide shared data and functionality across components.

I implement security standards such as HTTPS, encryption, firewalls, and regular security audits to secure a website.

• Implementing HTTPS to encrypt data transmitted between the website and users

• Using encryption algorithms to protect sensitive data stored on the server

• Setting up firewalls to monitor and control incoming and outgoing traffic

• Conducting regular security audits to identify and address vulnerabilities

• Implementing multi-factor authentication for user accounts

I would communicate with the stakeholders to understand the reasons for the changes and prioritize them accordingly.

• Communicate with stakeholders to understand the reasons for the changes

• Prioritize the changes based on impact and urgency

• Adjust the sprint plan and tasks accordingly

• Ensure clear documentation and communication with the team

SOLID principles help in creating maintainable, scalable, and flexible software.

• SOLID principles help in creating software that is easier to maintain and extend.

• Single Responsibility Principle (SRP) ensures that a class has only one reason to change, leading to more modular and cohesive code.

• Open/Closed Principle (OCP) states that a class should be open for extension but closed for modification, allowing for easy changes and additions without altering existing code.

• Violating ...read more

Answers to technical questions for Senior Software Engineer interview

• Webpack is a module bundler for JavaScript applications

• Optimizing React app can be done by code splitting, lazy loading, using production build, etc.

• Flexbox is for one-dimensional layout while Grid is for two-dimensional layout

• CSS box model is a way to represent the layout of HTML elements

Answers to questions related to Senior Software Engineer interview.

• 1. Different status codes in API include 200 (OK), 404 (Not Found), 500 (Internal Server Error), etc.

• 2. Framework creation involves identifying the requirements, selecting the tools and technologies, designing the architecture, and implementing the code.

• 3. Collection refers to a group of related objects or data that can be manipulated as a single entity. Examples include arrays, lists, and dictionaries.

• 4. Test...read more

State management libraries other than Redux

• MobX - simple and scalable state management

• Flux - unidirectional data flow architecture

• Vuex - state management for Vue.js

• Apollo Client - state management for GraphQL

• React Context API - built-in state management for React

• Recoil - experimental state management library for React

• XState - state management for finite state machines

A simple program using modulo operator to determine if a number is odd or even.

• Use the modulo operator (%) to check if the number divided by 2 leaves a remainder

• If the remainder is 0, the number is even. If the remainder is 1, the number is odd

• Example: num % 2 == 0 (even), num % 2 == 1 (odd)

HashMap is a data structure that stores key-value pairs and uses hashing to retrieve values quickly.

• HashMap uses an array of buckets to store key-value pairs

• Each bucket contains a linked list of entries with the same hash code

• When a key-value pair is added, its hash code is used to determine the bucket and added to the linked list

• When a value is retrieved, its hash code is used to find the bucket and search the linked list for the key

• HashMap uses load factor to determine when...read more

Table variable is a variable that holds a table-like structure in memory for temporary use.

• Table variables are declared using the DECLARE keyword in SQL Server.

• They can be used to store temporary data within a stored procedure or a batch of SQL statements.

• Table variables have a scope limited to the batch or stored procedure in which they are declared.

• They are automatically dropped when the batch or stored procedure completes execution.

• Table variables can be used in place of t...read more

Use a subquery to find the second highest rank in a dataset.

• Use a subquery to select the maximum rank from the dataset.

• Then use another subquery to select the maximum rank that is less than the maximum rank found in the first subquery.

var is function scoped, let is block scoped, and const is block scoped with read-only values.

• var is function scoped, meaning it is accessible throughout the function it is declared in.

• let is block scoped, meaning it is only accessible within the block it is declared in.

• const is block scoped like let, but the value cannot be reassigned.

SOLID and ACID are principles in software engineering and database management, respectively, to ensure code quality and data integrity.

• SOLID principles focus on object-oriented design and include Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, and Dependency Inversion.

• ACID principles ensure database transactions are processed reliably and include Atomicity, Consistency, Isolation, and Durability.

• Usage of SOLID principles leads to maintainable a...read more

with sharing enforces sharing rules, without sharing doesn't enforce sharing rules, inherited sharing uses the sharing rules of the parent class

• with sharing keyword enforces sharing rules specified in the organization-wide defaults

• without sharing keyword doesn't enforce sharing rules, allowing access to all records

• inherited sharing keyword uses the sharing rules of the parent class

Project flow involves understanding the sequence of tasks in a project. Exceptions are handled using try-catch blocks.

• Project flow involves defining the sequence of tasks from start to finish.

• Exceptions are handled using try-catch blocks to catch and handle errors gracefully.

• Logging and alerting mechanisms are implemented to track and notify about exceptions.

• Unit tests are written to cover different scenarios and ensure proper exception handling.

• Regular code reviews and debug...read more