4000+ Senior Software Engineer Interview Questions and Answers

The task is to find all pairs of elements in an array that add up to a given target.

• Iterate through the array and for each element, check if the target minus the element exists in a hashmap.

• If it exists, print the pair (current element, target - current element).

• If no pair is found, print (-1, -1).

The task is to find the Kth largest element in a given list of numbers for each test case.

• Read the number of test cases 'T'

• For each test case, read the number of elements 'N' and the value of 'K'

• Sort the array in descending order and output the Kth element

The task is to find the Next Greater Element for each element in a list of integers.

• Iterate through the list of integers from right to left

• Use a stack to keep track of elements for which the Next Greater Element is not yet found

• Pop elements from the stack until a greater element is found or the stack is empty

Generate the first 'X' terms of a series 3 * N + 2, excluding multiples of 4.

• Iterate through numbers starting from 1 and check if 3 * N + 2 is not a multiple of 4.

• Keep track of the count of terms generated and stop when 'X' terms are found.

• Return the list of terms that meet the criteria for each test case.

Answers to questions related to software engineering concepts.

• Volatile is a keyword used to indicate that a variable's value can be changed unexpectedly.

• Constant is a keyword used to indicate that a variable's value cannot be changed once it is assigned.

• Volatile and const can be used together to indicate that a variable's value cannot be changed and that it may change unexpectedly.

• ISR stands for Interrupt Service Routine and is a function that is called when an interrupt occu...read more

Lambda expression in Java is a concise way to represent a method implementation. It is related to functional interfaces by providing a single abstract method implementation.

• Lambda expressions allow you to write concise code by providing a way to represent a method implementation in a more compact form.

• Functional interfaces are interfaces with a single abstract method. Lambda expressions can be used to provide the implementation for this single method.

• For example, a functional...read more

Microflows and nanoflows are both used in Mendix for defining business logic, but they differ in their scope and complexity.

• Microflows are used for larger and more complex processes, while nanoflows are used for smaller and simpler processes.

• Microflows can have multiple activities and can be triggered by events, while nanoflows have a single activity and are typically called from microflows.

• Microflows can have input and output parameters, while nanoflows do not support parame...read more

Thread class is a class in Java that extends the Thread class, while Runnable interface is an interface that implements the run() method.

• Thread class extends the Thread class, while Runnable interface implements the run() method.

• A class can only extend one class, so using Runnable interface allows for more flexibility in the class hierarchy.

• Using Runnable interface separates the task from the thread, promoting better design practices.

• Example: Thread t = new Thread(new MyRunna...read more

Tech stack for designing a scalable Uber-like service.

• Use microservices architecture for scalability and fault tolerance.

• Choose a cloud provider with auto-scaling capabilities.

• Use a load balancer to distribute traffic across multiple instances.

• Use a NoSQL database for high availability and scalability.

• Use message queues for asynchronous communication between services.

• Use containerization for easy deployment and management.

• Use caching to improve performance.

• Use monitoring and ...read more

The question asks about using .every() and .includes() methods to check if each character of a string is present in another string.

• Loop through each element of the string

• Split the string into an array to access each character

• Use .every() method to check if each character is present in the user string

• Use .includes() method to check if the character is present

Autowiring in Spring Boot is a feature that allows Spring to automatically inject dependencies into a Spring bean.

• Autowiring eliminates the need for explicit bean wiring in the Spring configuration file.

• There are different modes of autowiring in Spring Boot: 'byName', 'byType', 'constructor', 'autodetect', and 'no'.

• For example, in 'byName' mode, Spring looks for a bean with the same name as the property that needs to be autowired.

Program to find the longest palindrome substring in a given string.

• Iterate through the string and check for palindromes of different lengths

• Store the longest palindrome found

• Return the length and substring

The CTC offered for this position is competitive and includes salary, benefits, and bonuses.

• CTC includes salary, benefits, bonuses, and other perks

• Negotiation may be possible based on experience and skills

• CTC details are typically discussed during the final stages of the interview process

Implemented JWT and OAuth authentication in Angular and .NET Core apps.

• Used Angular's HttpInterceptor to add JWT token to requests

• Implemented OAuth2 authentication using IdentityServer4 in .NET Core

• Stored user credentials securely using ASP.NET Core Identity

• Used HTTPS to encrypt data in transit

• Implemented role-based authorization using ASP.NET Core Identity

Custom hooks in React are reusable functions that allow you to extract component logic into separate functions for better code organization and reusability.

• Custom hooks are created using the 'use' prefix and can be used to share logic between components.

• Use cases for custom hooks include fetching data from an API, handling form state, managing local storage, and more.

• Example of a custom hook for API call: const useFetchData = (url) => { // logic to fetch data from API }

Clustered Index physically reorders the data in the table, while Non-Clustered Index creates a separate structure.

• Clustered Index determines the physical order of data rows in a table.

• Non-Clustered Index creates a separate structure that points back to the original table.

• Clustered Index is faster for retrieval of data, while Non-Clustered Index is faster for retrieval of specific rows.

• Example: Primary key in a table is usually implemented as a Clustered Index, while secondary...read more

Designing the Low-Level Design (LLD) and High-Level Design (HLD) for a system like BookMyShow.

• For HLD, identify main components like user interface, booking system, payment gateway, and database.

• For LLD, break down each component into detailed modules and their interactions.

• Consider scalability, security, and performance in both designs.

• Example: HLD - User selects movie -> Booking system checks availability -> Payment gateway processes transaction.

• Example: LLD - Booking syste...read more

Node.js is a server-side JavaScript runtime environment.

• Node.js is built on top of the V8 JavaScript engine from Google Chrome.

• It allows developers to write server-side code in JavaScript.

• Node.js has a non-blocking I/O model, making it efficient for handling large amounts of data.

• Node.js has a vast library of modules available through npm (Node Package Manager).

Print pairs of adjacent elements in an array

• Loop through the array and print each pair of adjacent elements

• Use a for loop and access the elements using their indices

• Example: for i in 0 until a.length-1 print (a[i], a[i+1])

The start() method is used to start a new thread, while the run() method contains the code that will be executed by the thread.

• start() method is used to start a new thread and calls the run() method internally

• run() method contains the code that will be executed by the thread

• It is recommended to override the run() method with the desired functionality

Integration, middleware, and EAI systems are technologies that enable communication and data exchange between different software applications.

• Integration involves connecting different software applications to enable data exchange and communication.

• Middleware is software that sits between different applications and facilitates communication and data exchange.

• EAI (Enterprise Application Integration) systems are a type of middleware that enable communication between different en...read more

Unix related questions for Senior Software Engineer interview

• A hard link is a direct link to the physical file on disk, while a symbolic link is a reference to the file by name.

• To find out the system's IP address in Unix, you can use commands like ifconfig or ip addr show.

• The chmod command in Unix is used to change the permissions of a file or directory.

• grep is used for searching text using regular expressions, while egrep is an extended version of grep with more powerful pat...read more

Designing a database schema for a support ticketing system like Freshdesk.

• Create a 'Tickets' table with fields like ticket ID, subject, description, status, priority, etc.

• Include a 'Users' table for customer and agent information.

• Establish a 'Categories' table for ticket categorization.

• Implement a 'Comments' table to track communication history.

• Utilize foreign keys to establish relationships between tables.

The biggest challenge in developing Azure solution was managing the complexity of the cloud environment.

• Managing the complexity of the cloud environment

• Ensuring scalability and reliability

• Integrating with existing systems

• Securing the solution

• Optimizing cost

• Example: Migrating a legacy application to Azure

DELETE removes specific rows from a table, while TRUNCATE removes all rows and resets auto-increment values.

• DELETE is a DML command, while TRUNCATE is a DDL command.

• DELETE can be rolled back, while TRUNCATE cannot be rolled back.

• DELETE triggers ON DELETE triggers, while TRUNCATE does not trigger any triggers.

• DELETE is slower as it logs individual row deletions, while TRUNCATE is faster as it logs the deallocation of data pages.

• Example: DELETE FROM table_name WHERE condition; ...read more

Java is platform independent because it compiles code into bytecode that can run on any system with a JVM, which is platform dependent.

• Java code is compiled into bytecode, which is platform independent

• The JVM interprets the bytecode and translates it into machine code specific to the underlying platform

• This allows Java programs to run on any system with a JVM installed, making Java platform independent

Common testing questions related to Linux and operating systems

• What are the different types of testing that can be performed on a Linux operating system?

• How do you test the compatibility of software with different Linux distributions?

• Can you explain the process of testing kernel modules in a Linux environment?

• What tools and techniques do you use for performance testing on Linux systems?

• How do you ensure the security and stability of a Linux server through testing?

Modifying the POCO class allows extending the entity with additional properties.

• To add extra properties, simply modify the POCO class by adding new properties.

• Ensure that the changes are reflected in the database schema if necessary.

• Update any existing code that interacts with the POCO class to handle the new properties.

• Consider the impact on serialization, validation, and any other relevant aspects.

The color applied will be based on the specificity of the selector, with ID having higher specificity than class.

• ID has higher specificity than class in CSS

• Color applied will be based on the selector with higher specificity

• Example: If ID selector has color red and class selector has color blue, the color applied will be red

The code will throw an error because 'a' is declared but not initialized.

• The code will result in a ReferenceError because 'a' is declared but not assigned a value.

• Variables declared with 'const' must be initialized at the time of declaration.

• Initializing 'a' with a value before calling test() will prevent the error.

There are three types of variables in Java: local, instance, and static.

• Local variables are declared within a method or block and have limited scope.

• Instance variables are declared within a class but outside of any method and are accessible to all methods of the class.

• Static variables are declared with the static keyword and are shared among all instances of the class.

• Examples: int x; //instance variable, static int y; //static variable, void method() { int z; //local variabl...read more

SOLID principles are a set of five design principles in object-oriented programming to make software designs more understandable, flexible, and maintainable.

• S - Single Responsibility Principle: A class should have only one reason to change.

• O - Open/Closed Principle: Software entities should be open for extension but closed for modification.

• L - Liskov Substitution Principle: Objects of a superclass should be replaceable with objects of its subclasses without affecting the func...read more

Parallel stream is not always beneficial in Java Stream API.

• Parallel stream can be slower than sequential stream for small data sets or when the overhead of parallelism is greater than the benefit.

• Parallel stream can be beneficial for large data sets or when the operations are independent and can be executed in parallel.

• It is important to measure the performance of both sequential and parallel streams for a specific use case to determine which is more efficient.

Program to find last non-repeating character in a given string using Java 8 functions only.

• Use Java 8 Streams and Lambda's to filter the string and find the last non-repeating character.

• Create a Map to store the frequency of each character in the string.

• Use the filter() method to get the non-repeating characters and find the last one using reduce().

Autowiring in Spring Boot is a way to automatically inject dependencies into Spring beans.

• Autowiring is a feature in Spring that allows the container to automatically inject the dependencies of a bean.

• There are different modes of autowiring in Spring: 'byName', 'byType', 'constructor', 'autodetect', and 'no'.

• For example, in 'byName' autowiring, Spring looks for a bean with the same name as the property being autowired.

The starter dependency of the Spring Boot module is spring-boot-starter-parent.

• The starter dependency of Spring Boot provides a set of default configurations and dependencies to kickstart a Spring Boot project.

• It includes commonly used dependencies like spring-boot-starter-web, spring-boot-starter-data-jpa, etc.

• The spring-boot-starter-parent also manages the versions of all dependencies to ensure compatibility.

I am highly proficient in HTML, CSS, and JavaScript.

• Extensive experience in building responsive web applications using HTML, CSS, and JavaScript

• Strong understanding of front-end frameworks like React, Angular, or Vue.js

• Familiarity with CSS preprocessors like SASS or LESS

• Knowledge of modern JavaScript ES6+ features and best practices

• Experience in optimizing web performance and cross-browser compatibility

Answering questions related to creating GQL server, directives, fragments, unit tests, TypeScript features, and React.js functionalities.

• To create a GQL server, you can use tools like Apollo Server or Express with GraphQL middleware.

• Directives in GQL are used to modify the behavior of a field or fragment in a query. For example, @include and @skip are common directives.

• Fragments in GQL allow you to define reusable units of query logic. They can be included in queries to avoid...read more

Delegates are reference types that hold a reference to a method. They are used to achieve loose coupling and event handling.

• Delegates allow methods to be passed as parameters to other methods.

• They can be used to define callback methods.

• Built-in delegates in C# include Action, Func, Predicate, EventHandler, and Comparison.

• Action and Func are used for methods that return void and non-void values respectively.

• Predicate is used for methods that return a Boolean value.

• EventHandler...read more

let, var, and const are all used to declare variables in JavaScript, but they have different scoping rules and behaviors.

• let and const were introduced in ES6, while var has been around since the beginning of JavaScript.

• let and const are block-scoped, while var is function-scoped.

• Variables declared with const cannot be reassigned, while let and var can be.

• const variables must be initialized when they are declared, while let and var can be declared without initialization.

• Exampl...read more

List is mutable and Tuple is immutable in Python.

• List can be modified after creation while Tuple cannot be modified.

• List uses square brackets [] while Tuple uses parentheses ().

• List is used for homogenous data while Tuple is used for heterogenous data.

• List is slower than Tuple in terms of performance.

• Example of List: [1, 2, 3] and Example of Tuple: (1, 'hello', 3.14)

The program prints a star pattern using asterisks and spaces.

• Use nested loops to iterate through rows and columns.

• Determine the number of asterisks and spaces to print in each row.

• Use conditional statements to decide when to print an asterisk or a space.

Implement an API in Java to fetch top rated movies in a certain genre from an external datasource using pagination.

• Create a REST API endpoint in Java using Spring Boot framework

• Implement pagination by using query parameters for 'page' and 'size'

• Filter the movies by genre and sort them by rating to fetch the top rated ones

• Use a service layer to interact with the external datasource and fetch the data

• Return the filtered and paginated movie data in the response

To switch between tabs in a browser using Selenium, we can use the getWindowHandles() method and switchTo() method.

• Use getWindowHandles() method to get the handles of all open tabs

• Store the handles in a Set

• Use switchTo() method to switch to a specific tab by passing the handle as an argument

Spring Boot offers basic annotations like @SpringBootApplication, @RestController, @Autowired, @RequestMapping, @Component, @Service, @Repository.

• @SpringBootApplication - Used to mark the main class of a Spring Boot application.

• @RestController - Used to define a RESTful controller.

• @Autowired - Used for automatic dependency injection.

• @RequestMapping - Used to map web requests to specific handler methods.

• @Component - Used to indicate a class is a Spring component.

• @Service - Use...read more

The @SpringBootApplication annotation is used to mark the main class of a Spring Boot application.

• It is a combination of @Configuration, @EnableAutoConfiguration, and @ComponentScan annotations.

• It tells Spring Boot to start adding beans based on classpath settings, other beans, and various property settings.

• It is often placed on the main class that contains the main method to bootstrap the Spring Boot application.

Implement strategies to resolve backlog of requests from microservice two due to microservice three breaking.

• Identify the root cause of the issue in microservice three and fix it.

• Implement circuit breaker pattern to handle failures and prevent cascading failures.

• Implement retries with exponential backoff for failed requests from microservice two to microservice three.

• Scale up microservice three to handle increased load from microservice two.

• Implement message queues or asynchr...read more