3500+ 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.

To find code performance issues in production, use monitoring tools and profiling techniques.

• Use monitoring tools like New Relic, AppDynamics, or Datadog to track performance metrics and identify bottlenecks.

• Use profiling techniques like CPU profiling, memory profiling, and network profiling to pinpoint specific areas of the code that are causing performance issues.

• Analyze logs and error messages to identify patterns and potential performance issues.

• Perform load testing and s...read more