100+ Vector Wings Technologies Interview Questions and Answers

Implementing security measures for microservices involves using authentication, authorization, encryption, and monitoring.

• Implement authentication mechanisms such as OAuth, JWT, or API keys to verify the identity of clients accessing the microservices.

• Enforce authorization rules to control access to different parts of the microservices based on roles and permissions.

• Use encryption techniques like TLS/SSL to secure communication between microservices and external clients.

• Imple...read more

Add two linked lists representing numbers and return the resulting linked list.

• Traverse both linked lists and add the corresponding digits, keeping track of carry.

• Create a new node for each digit and update the carry for the next iteration.

• If one list is longer than the other, add the remaining digits to the result.

• Handle the case where the carry is not zero after all digits have been added.

• Time complexity: O(max(m,n)), where m and n are the lengths of the input lists.

I remain calm, listen actively, empathize with their situation, apologize for any inconvenience, and work towards finding a solution.

• Remain calm and composed

• Listen actively to understand their concerns

• Empathize with their situation

• Apologize for any inconvenience caused

• Work towards finding a solution to address their issue

Props are short for properties and are used to pass data from parent to child components in React.

• Props are read-only and cannot be modified by the child component.

• Props are passed down from parent to child components using attributes.

• Props can be any type of data, including strings, numbers, arrays, objects, or functions.

• Example: <ChildComponent name='John' age={25} />

My approach to building basic logic skills involves practicing problem-solving exercises, breaking down complex problems into smaller parts, and seeking feedback to improve.

• Practice problem-solving exercises regularly to strengthen logical thinking abilities.

• Break down complex problems into smaller, more manageable parts to better understand the problem and find solutions.

• Seek feedback from peers or mentors to identify areas for improvement and refine logic skills.

• Utilize res...read more

Use binary search to find the first and last occurrence of the character, then calculate the frequency.

• Use binary search to find the first occurrence of the character in the string.

• Use binary search to find the last occurrence of the character in the string.

• Calculate the frequency by subtracting the indices of the last and first occurrences and adding 1.

Sync API waits for a response before continuing, while Async API allows the program to continue executing without waiting for a response.

• Sync API is blocking and waits for a response before proceeding

• Async API is non-blocking and allows the program to continue executing while waiting for a response

• Sync microservice handles requests sequentially, while Async microservice can handle multiple requests concurrently

• Example of Sync API: REST API that waits for a response before ret...read more

Method overriding in Java with code example

• Output will be 'Child class method' as the method in Child class overrides the method in Parent class

• Method overriding is a feature that allows a subclass to provide a specific implementation of a method that is already provided by its superclass

• The method in the subclass should have the same name, return type, and parameters as the method in the superclass

OOPs concepts and pillars. Design a Vehicle class based on requirements.

• OOPs concepts: Abstraction, Encapsulation, Inheritance, Polymorphism

• Vehicle class requirements: attributes like make, model, year, methods like start, stop, accelerate

An IP address can be found by checking network settings, using command prompt, or using online tools.

• Check network settings on your device

• Use command prompt and type 'ipconfig' for Windows or 'ifconfig' for Mac/Linux

• Use online tools like 'WhatIsMyIP.com' or 'IP-Address.com'

Answers to various technical questions related to programming and database concepts.

• throw is used to throw an exception in Java, while throws is used in method signature to declare the exceptions that can be thrown by the method

• JIT compiler stands for Just-In-Time compiler, which compiles Java bytecode into native machine code at runtime for improved performance

• Compiler is a software program that translates high-level programming languages into machine code, while compellers ...read more

Redux is a predictable state container for JavaScript apps.

• Redux stores the entire state of an application in a single immutable object.

• State changes are made by dispatching actions, which are plain JavaScript objects.

• Reducers specify how the state changes in response to actions.

• Components can subscribe to the Redux store to access the state and re-render when it changes.

Saga pattern is used to manage distributed transactions in microservices by breaking them into smaller, independent transactions.

• Saga pattern involves breaking down a long transaction into a series of smaller, independent transactions.

• Each step in the saga is a separate transaction that can be rolled back if needed.

• Compensating transactions are used to undo the effects of a previously completed step in case of failure.

• Sagas can be implemented using choreography or orchestrati...read more

Question on internal working of hashmap, multi-threading, DSA, and coding.

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

• Multi-threading is the ability of a CPU to execute multiple threads concurrently.

• DSA stands for Data Structures and Algorithms, which are fundamental concepts in computer science.

• Coding involves writing instructions in a programming language to create software applications.

Create a REST api to fetch user details using userId

• Create a GET endpoint /users/{userId} to fetch user details

• Use userId as a parameter in the endpoint

• Return user details in JSON format

• Handle errors for invalid userId

Create a global exception handler class for UserNotFound exception.

• Create a class that extends ExceptionHandler class

• Override the handleException method to handle UserNotFound exception

• Implement the logic to handle the exception, such as logging or returning a custom error message

Redux is a predictable state container for JavaScript apps.

• Redux is a state management library for JavaScript applications.

• It provides a centralized store to manage the state of an application.

• Redux follows a unidirectional data flow pattern.

• Actions are dispatched to update the state in the store.

• Reducers are pure functions that update the state based on the dispatched actions.

• Selectors are used to retrieve data from the store.

• Middleware can be used to intercept and modify ac...read more

Memory management in Python involves automatic memory allocation and deallocation through garbage collection.

• Python uses automatic memory management through garbage collection to allocate and deallocate memory.

• Memory is managed using reference counting and a cycle-detecting garbage collector.

• Python's memory management is efficient for most use cases, but can lead to memory leaks if circular references are not handled properly.

Garbage collection in Python is an automatic memory management process that helps in reclaiming memory occupied by objects that are no longer in use.

• Python uses a built-in garbage collector to manage memory automatically.

• The garbage collector in Python uses reference counting and a cycle-detecting algorithm to reclaim memory.

• Explicitly calling the 'gc.collect()' function can trigger garbage collection in Python.

• Garbage collection helps in preventing memory leaks and optimizin...read more

Program to check if a number is prime or not

• A prime number is only divisible by 1 and itself

• Loop through numbers from 2 to n-1 and check if n is divisible by any of them

• If n is divisible by any number, it is not prime

• If n is not divisible by any number, it is prime

Redux is a predictable state container for JavaScript apps.

• Redux is a state management library for JavaScript applications.

• It helps in managing the state of an application in a predictable way.

• Redux stores the entire state of the application in a single immutable object.

• Actions are dispatched to update the state, and reducers specify how the state changes in response to actions.

• Redux is commonly used with React to manage the state of complex applications.

NoSQL databases are non-relational databases that store and retrieve data in a non-tabular format.

• Document-oriented databases (MongoDB, Couchbase)

• Key-value stores (Redis, Riak)

• Column-family stores (Cassandra, HBase)

• Graph databases (Neo4j, OrientDB)

One of my weaknesses is procrastination.

• I tend to put off tasks until the last minute.

• To overcome this, I have started using time management techniques such as the Pomodoro technique.

• I also try to break down tasks into smaller, more manageable chunks.

• I have found that setting deadlines for myself and holding myself accountable helps me stay on track.

Hashing is a process of converting data into a fixed-size output. It has a key that is used to access the data.

• Hashing is used to store and retrieve data quickly.

• It uses a hash function to generate a unique key for each input data.

• The key is used to access the data in constant time.

• Hashing is used in password storage, data indexing, and cryptography.

• Examples of hash functions include MD5, SHA-1, and SHA-256.

Functional components are simpler and easier to test, while class components have more features and better performance.

• Functional components are stateless and use hooks for state management.

• Class components have lifecycle methods and can hold state.

• Functional components are easier to read and write.

• Class components have better performance in certain scenarios.

• Functional components are recommended for simple UI components.

• Class components are recommended for complex UI compone...read more

Factorial of n and sum of n numbers using recursion

• Create a recursive function to calculate factorial of n

• Use a recursive function to calculate the sum of all n numbers

• Handle base cases for both factorial and sum calculations

• Example: Factorial of 5 = 5 * 4 * 3 * 2 * 1 = 120, Sum of first 5 numbers = 1 + 2 + 3 + 4 + 5 = 15

Find the second largest element from the array.

• Sort the array in descending order and return the second element.

• Iterate through the array and keep track of the two largest elements.

• Use a priority queue to find the second largest element.

A stack is a linear data structure that follows the Last In First Out (LIFO) principle.

• Elements are added to the top of the stack and removed from the top as well.

• Common operations include push (add element to top) and pop (remove element from top).

• Stacks can be implemented using arrays or linked lists.

• Example: undo/redo functionality in a text editor.

• Example: function call stack in programming languages.

Acknowledge their frustration, actively listen, empathize, apologize, offer a solution or escalate if necessary.

• Remain calm and professional

• Use active listening skills

• Empathize with the user's frustration

• Apologize for any inconvenience caused

• Offer a solution or escalate to a higher level of support if necessary

• Provide clear and concise communication throughout the interaction

Permutations of a string

• Use recursion to swap characters and generate permutations

• Iterate through the string and swap each character with the first character

• Repeat the above step for each character in the string

To fetch all duplicate values from an array of strings

• Iterate through the array and store each element in a HashSet

• If an element is already in the HashSet, it is a duplicate value

• Add the duplicate values to a separate list and return it

Scaling refers to the process of increasing or decreasing the capacity of a system to handle more or less load.

• Vertical Scaling: Adding more resources to a single node

• Horizontal Scaling: Adding more nodes to a system

• Load Balancing: Distributing the load across multiple nodes

• Database Sharding: Splitting a database into smaller parts to distribute the load

• Caching: Storing frequently accessed data in memory for faster access

SOLID principles and best coding practices are essential for creating maintainable and scalable software.

• S - Single Responsibility Principle: Each class should have only one responsibility.

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

• L - Liskov Substitution Principle: Subtypes should be substitutable for their base types.

• I - Interface Segregation Principle: Clients should not be forced to depend on interfaces they do not use.

• D - ...read more

Angular is a popular front-end framework for building web applications.

• Angular is developed and maintained by Google.

• It uses TypeScript for building scalable and maintainable applications.

• Angular has a powerful CLI for generating components, services, and more.

• It has a large and active community with many third-party libraries and plugins available.

• Angular has a modular architecture that allows for easy code reuse and testing.

Sort array and return second last element

• Use built-in sort function

• Access second last element using array index -2

JDK is a development kit, JRE is a runtime environment, and JVM is a virtual machine. Equals compares object values, HashCode returns a unique integer for an object.

• JDK includes JRE and development tools, while JRE includes JVM and necessary libraries

• JVM is responsible for executing Java bytecode

• Equals method compares the values of two objects, while == compares their references

• HashCode method returns a unique integer for an object, used for hashing and storing objects in col...read more

A cursor is a database object used to retrieve data from a result set one row at a time.

• A cursor is used to iterate through a result set.

• It can be used to update or delete rows in a table.

• Example query: DECLARE cursor_name CURSOR FOR SELECT column1, column2 FROM table_name;

• Example usage: OPEN cursor_name; FETCH NEXT FROM cursor_name INTO @variable1, @variable2;

• Example usage: CLOSE cursor_name; DEALLOCATE cursor_name;

Finding common characters in 3 strings using coding

• Create a function that takes in 3 strings as input

• Iterate through each character of the first string and check if it exists in the other 2 strings

• Store the common characters in an array and return it

Inter service communication in transactional systems involves designing a reliable and efficient way for services to communicate and exchange data.

• Use asynchronous messaging systems like RabbitMQ or Kafka to decouple services and ensure reliable message delivery.

• Implement RESTful APIs for synchronous communication between services, using HTTP methods like GET, POST, PUT, DELETE.

• Consider using gRPC for high-performance, low-latency communication between services, especially in...read more

Use pandas library for efficient loading and processing of large files in Python.

• Use pandas read_csv() function with chunksize parameter to load large files in chunks.

• Optimize memory usage by specifying data types for columns in read_csv() function.

• Use pandas DataFrame methods like groupby(), merge(), and apply() for efficient data processing.

• Consider using Dask library for parallel processing of large datasets.

• Use generators to process data in chunks and avoid loading entire...read more

Use a nested loop to iterate through the array and check for the sum of squares of two elements equal to the square of a third element.

• Iterate through the array using a nested loop to compare all possible combinations of elements.

• Calculate the sum of squares of two elements and check if it equals the square of a third element.

• Return the elements if a match is found, otherwise continue iterating.

Designing a parking system for efficient management of parking spaces.

• Utilize sensors to detect available parking spaces

• Implement a reservation system for users to book parking spots in advance

• Incorporate a payment system for users to pay for parking

• Include a monitoring system to track occupancy levels and manage traffic flow

Left view of a binary tree

• The left view of a binary tree shows the leftmost node at each level

• We can traverse the tree in a pre-order fashion and keep track of the current level

• If the current level is greater than the maximum level seen so far, add the node to the result

Spring Boot is a framework that simplifies the development of Java applications by providing pre-configured settings and tools.

• Spring Boot eliminates the need for manual configuration by providing defaults for most settings.

• It allows developers to create stand-alone, production-grade Spring-based Applications.

• Spring Boot includes an embedded Tomcat, Jetty, or Undertow server, making it easy to deploy web applications.

• It provides a range of features such as auto-configuration,...read more

useRef is a hook used to create a mutable ref object, while createRef is a method used to create a ref object.

• useRef is a hook provided by React, while createRef is a method provided by the React library.

• useRef can be used in functional components to create a mutable ref object that persists across renders.

• createRef is used in class components to create a ref object that can be attached to a DOM element.

• useRef can also be used to store any mutable value, not just DOM elements...read more

DevOps is a software development methodology that combines software development (Dev) with IT operations (Ops) to improve collaboration and efficiency.

• DevOps focuses on automating and streamlining the software development process.

• It involves continuous integration, continuous delivery, and continuous deployment.

• DevOps aims to shorten the system development life cycle and provide continuous delivery of high-quality software.

• Tools commonly used in DevOps include Jenkins, Docker...read more

Stream.map() transforms each element in a stream, while Stream.flatMap() transforms each element into a stream of values.

• map() applies a function to each element in a stream and returns a new stream with the transformed elements.

• flatMap() applies a function that returns a stream for each element in the original stream, then flattens the streams into a single stream of values.

• Example: map() - Stream.of(1, 2, 3).map(x -> x * 2) returns Stream.of(2, 4, 6).

• Example: flatMap() - St...read more

ETL pipeline procedures involve extracting data from various sources, transforming it, and loading it into a target database.

• Extract data from source systems using tools like Informatica, Talend, or Apache Nifi

• Transform data by cleaning, filtering, aggregating, and enriching it using SQL, Python, or Spark

• Load the transformed data into a target database such as MySQL, PostgreSQL, or Redshift

Print duplicate elements in an Array of strings

• Iterate through the array and use a HashMap to store frequency of each element

• Print elements with frequency greater than 1 as duplicates

IOC in Spring and DI offer flexibility, maintainability, and testability in software development.

• Promotes loose coupling between components

• Allows for easier unit testing and mocking

• Facilitates easier configuration and management of dependencies

• Enables better separation of concerns

• Promotes reusability of components

I utilized Marketo tool for creating and executing marketing campaigns, managing leads, and analyzing campaign performance.

• Created and automated email campaigns to nurture leads

• Built landing pages and forms to capture lead information

• Segmented leads based on behavior and demographics for targeted campaigns

• Analyzed campaign performance and adjusted strategies accordingly

Questions on volatile, gdb usage, and singleton pattern.

• Volatile is a keyword in C that tells the compiler not to optimize the variable.

• GDB is a debugger tool used to analyze and debug code during runtime.

• Singleton is a design pattern that restricts the instantiation of a class to one object.

• To use GDB, compile the code with the -g flag, run the executable with gdb, set breakpoints, and use commands like 'next' and 'print'.

• An example of using the singleton pattern is creating...read more

Custom ordering in SQL allows you to specify the order in which results are returned.

• Use ORDER BY clause in SQL to specify custom ordering

• You can order by multiple columns and specify ASC (ascending) or DESC (descending) order

• Example: SELECT * FROM table_name ORDER BY column_name ASC;

Clustering depth in Snowflake refers to the number of levels in the clustering key hierarchy.

• Clustering depth determines the granularity of data organization within Snowflake tables.

• A higher clustering depth means more levels in the clustering key hierarchy, allowing for more specific data organization.

• Clustering depth can impact query performance and storage efficiency in Snowflake.

Backup and recovery is the process of creating and restoring data in case of data loss or corruption.

• Backup involves creating a copy of data to protect against data loss or corruption.

• Recovery involves restoring the data from the backup in case of data loss or corruption.

• There are different types of backups such as full, incremental, and differential backups.

• Backup and recovery is important for ensuring business continuity and minimizing downtime.

• Examples of backup and recove...read more

API to save data in Java

• Use HTTP POST method to send data to the server

• Create a RESTful endpoint to handle the data saving

• Validate the input data before saving it to the database

There are multiple ways to iterate over a HashMap in Java.

• Using keySet() and values() methods

• Using entrySet() method

• Using forEach() method with lambda expression

Test framework is a set of guidelines, coding standards, and best practices to perform automated testing efficiently.

• Test framework provides a structure for organizing and executing automated tests.

• It includes libraries, tools, and utilities to simplify test creation and maintenance.

• Test framework helps in reducing the time and effort required for testing.

• Examples of test frameworks are Selenium, TestNG, JUnit, and NUnit.

A top view of a binary tree shows the nodes visible from the top when looking down from the root node.

• The top view of a binary tree can be obtained by performing a level order traversal and keeping track of the horizontal distance of each node from the root.

• Nodes with the same horizontal distance are at the same level in the top view.

• Example: For the binary tree 1 -> 2 -> 3 -> 4 -> 5, the top view would be 1 -> 2 -> 3 -> 4 -> 5.

Replication is the process of copying and distributing data from one database to another.

• Replication is used to improve data availability and increase scalability.

• It can be done in real-time or on a schedule.

• There are different types of replication, such as snapshot replication, transactional replication, and merge replication.

• Examples of replication software include Oracle GoldenGate, Microsoft SQL Server Replication, and MySQL Replication.

Spring IOC (Inversion of Control) is a design pattern where the control of object creation and lifecycle is shifted to a container.

• In Spring IOC, objects are created and managed by the Spring container.

• Types of Spring IOC include Constructor-based dependency injection and Setter-based dependency injection.

• Example: In Constructor-based dependency injection, dependencies are provided through the constructor of a class.

• Example: In Setter-based dependency injection, dependencies ...read more

Circuit Breaker is a design pattern used in software development to prevent system overload and failures.

• Circuit Breaker monitors the number of failures and opens when a threshold is reached.

• It can be in states like closed, open, or half-open.

• Closed state allows normal operation, open state prevents further requests, and half-open state allows limited requests to check if the system is back to normal.

• Examples include Hystrix in Java and Polly in .NET.

Threads are lightweight processes within a program that can run concurrently, allowing for multitasking and improved performance.

• Threads allow for parallel execution of tasks within a program.

• Threads share the same memory space, allowing for efficient communication and data sharing.

• Examples of using threads include running background tasks while the main program continues to execute, or handling multiple client requests simultaneously in a server application.

Some popular SEO tools include SEMrush, Ahrefs, Moz, Google Search Console, and Screaming Frog.

• SEMrush - for keyword research, site audits, and competitor analysis

• Ahrefs - for backlink analysis and keyword tracking

• Moz - for site audits, keyword research, and rank tracking

• Google Search Console - for monitoring website performance in Google search results

• Screaming Frog - for website crawling and technical SEO analysis

Upgradation refers to the process of upgrading or updating a system or software to a newer version or better quality.

• Upgradation involves replacing an older version of a system or software with a newer version.

• It can also involve adding new features or improving the existing ones.

• Upgradation is important to ensure that the system or software remains secure and compatible with other systems.

• Examples of upgradation include upgrading from Windows 7 to Windows 10, or upgrading fr...read more

Implement a data structure and algorithm for finding repeated elements in an array.

• Use a hash map to store the frequency of each element in the array.

• Iterate through the array and update the frequency in the hash map.

• Return the elements with frequency greater than 1 as the repeated elements.

Implementing DSA for sorting array of strings

• Use a sorting algorithm like bubble sort, selection sort, or merge sort

• Compare strings using built-in comparison functions or custom comparison functions

• Ensure the sorting algorithm is efficient and handles edge cases

JDBC Connection steps

• Load the JDBC driver class

• Establish a connection to the database using the DriverManager class

• Create a statement object to execute SQL queries

• Execute the SQL query and retrieve the results

• Process the results

• Close the statement and connection

Closures are functions that have access to variables in their outer scope, even after the outer function has returned.

• Closures are created when a function is defined inside another function.

• The inner function has access to the outer function's variables and parameters.

• Closures can be used to create private variables and methods.

• Closures can also be used to create functions with pre-set arguments.

K8s, short for Kubernetes, is a popular open-source container orchestration platform used for automating deployment, scaling, and management of containerized applications.

• Kubernetes automates the deployment, scaling, and management of containerized applications.

• It provides features like self-healing, load balancing, and rolling updates.

• Kubernetes uses declarative configuration files to define the desired state of the application.

• It supports various deployment strategies like ...read more

JPA implementation is a Java specification for mapping Java objects to relational databases.

• JPA stands for Java Persistence API.

• It provides a set of annotations and APIs for managing relational data in Java applications.

• JPA allows developers to write database-independent code.

• It supports object-relational mapping (ORM) and provides features like entity mapping, query language, and transaction management.

• Popular JPA implementations include Hibernate, EclipseLink, and OpenJPA.

Merge Sort is a divide and conquer algorithm that divides the input array into two halves, sorts them recursively, and then merges them.

• Divide the array into two halves

• Recursively sort each half

• Merge the sorted halves back together