70+ Interview Questions and Answers

Answers to common questions related to APIs, API management, and Apigee Edge

• API stands for Application Programming Interface and is a set of protocols and tools for building software applications

• APIs are popular because they allow different software systems to communicate and share data with each other

• API management involves the process of creating, publishing, documenting, and analyzing APIs

• Apigee Edge is an API management tool that provides features such as security, analyt...read more

Interview questions for Project Associate position covering OOPS concepts, MVC, ADO.NET, and SQL.

• Four pillars of OOPS: Abstraction, Encapsulation, Inheritance, Polymorphism

• Abstract class: Cannot be instantiated, can have abstract and non-abstract methods

• Interfaces: Contract that defines a set of methods, can be implemented by classes

• Finalize method: Called by garbage collector before object is destroyed

• Dispose method: Used to release unmanaged resources, should be called expl...read more

Answers to technical interview questions on Java programming language.

• To display most frequent element in an array using Streams and Lambda expression, use Collectors.groupingBy() and Collectors.counting() methods.

• ArrayList is an ordered collection of elements while HashSet is an unordered collection of unique elements.

• Default methods in interface are used to provide a default implementation of a method that can be overridden by implementing classes.

• StringBuffer is synchroniz...read more

Debugging using gdb and writing commands

• Compile the code with -g flag to include debugging information

• Start gdb with the executable file as argument

• Set breakpoints using 'break' command

• Run the program using 'run' command

• Use 'next' or 'step' command to execute the code line by line

• Print variable values using 'print' command

• Use 'backtrace' command to see the call stack

• Exit gdb using 'quit' command

Commands to push a file to a repository are add, commit, push.

• Use 'git add ' to stage the changes

• Use 'git commit -m ' to commit the changes

• Use 'git push' to push the changes to the remote repository

Unit testing is a software testing technique where individual units or components of a software application are tested in isolation.

• Unit testing helps to identify defects early in the development cycle

• It ensures that each unit of code is working as expected

• Unit tests are automated and can be run frequently to catch regressions

• Popular unit testing frameworks include JUnit for Java, NUnit for .NET, and pytest for Python

Explaining @Transactional, @Value, @Id, bean lifecycle and scopes

• Transactional is used to manage transactions in Spring

• Value is used to inject values from properties files or environment variables

• Id is used to mark a field as the primary key of an entity

• Bean lifecycle includes instantiation, initialization, use and destruction

• Scopes of bean include singleton, prototype, request, session, and global session

Data flows from Data Warehouse to downstream through ETL process and data transformation.

• Data is extracted from Data Warehouse using ETL tools like Informatica, Talend, etc.

• Data is transformed and cleansed using various data transformation techniques.

• Transformed data is loaded into downstream systems like Hadoop, Spark, etc.

• Data is dumped into downstream systems for further processing and analysis.

I am currently working on the Scrum process of Agile and using Jira as the tool for project management.

• I am following the Scrum framework of Agile which involves iterative and incremental development.

• I am responsible for facilitating daily stand-up meetings, sprint planning, sprint review, and retrospective meetings.

• Jira is the tool we are using for project management, which helps us to track the progress of tasks, assign them to team members, and monitor the overall project ...read more

Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine.

• Node.js allows for server-side scripting and event-driven programming.

• It has a large and active community with a vast number of libraries and modules available.

• Node.js is known for its scalability and high performance.

• Cons include potential security vulnerabilities and difficulty in debugging asynchronous code.

• Node.js is commonly used for web applications, real-time chat applications, and IoT devices.

Match and merge rules determine how records are matched and merged in a database. Match level refers to the criteria used to identify potential matches, while search level refers to the process of finding and comparing those potential matches.

• Match rules define the criteria used to identify potential matches between records.

• Merge rules determine how those potential matches are combined into a single record.

• Match level refers to the criteria used to identify potential matches,...read more

Provisioning tool is used to automate the process of setting up and managing resources. Layout designer is a tool to design the layout of the provisioning portal. Reference entity is a data model used in provisioning.

• Provisioning tool automates the process of setting up and managing resources

• Layout designer is a tool to design the layout of the provisioning portal

• Reference entity is a data model used in provisioning

• Provisioning tools include Chef, Puppet, Ansible, etc.

• Layout ...read more

Microservices are small, independent, and loosely coupled services that work together to form a larger application.

• Microservices are independently deployable and scalable.

• Each microservice performs a specific task and communicates with other services through APIs.

• Monolithic applications are a single, tightly-coupled unit, while microservices are modular and flexible.

• Microservices allow for faster development and easier maintenance.

• Examples of microservices include Amazon, Net...read more

Single threaded operation refers to the execution of a program using only one thread of execution.

• Single threaded programs can only perform one task at a time.

• They are simpler to write and debug than multi-threaded programs.

• Examples of single threaded programs include most console applications and simple scripts.

• Single threaded programs can be less efficient than multi-threaded programs when dealing with complex tasks or large amounts of data.

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

• Spring Boot uses the concept of 'beans' to manage application components and their dependencies.

• Beans are Java objects that are instantiated, assembled, and managed by the Spring IoC container.

• The scope of a bean determines its lifecycle and visibility within the application context.

• There are several bean scopes in Spring Boot, including single...read more

Agile is a project management methodology that emphasizes flexibility, collaboration, and iterative development.

• Agile values individuals and interactions over processes and tools

• It emphasizes working software over comprehensive documentation

• It involves frequent communication and collaboration between team members

• It encourages adapting to change rather than following a rigid plan

• Examples of agile methodologies include Scrum, Kanban, and Extreme Programming

Sleep and wait are methods used in Thread class in Java for pausing the execution of a thread.

• Sleep method pauses the execution of the current thread for a specified amount of time.

• Wait method pauses the execution of the current thread until another thread notifies it to resume.

• Sleep method does not release the lock on the object while wait method releases the lock on the object.

• Sleep method is used for delay whereas wait method is used for synchronization.

• Example: Thread.sle...read more

SwiftLint is a tool to enforce Swift style and conventions.

• SwiftLint is used to ensure consistent coding style and best practices in Swift code.

• It can be integrated into Xcode or run as a command line tool.

• SwiftLint checks for issues such as unused code, trailing whitespace, and naming conventions.

• It can be customized with rules and configurations to fit specific project needs.

Different techniques of performance tuning include indexing, query optimization, caching, and code refactoring.

• Indexing: Creating indexes on frequently queried columns to improve search performance.

• Query optimization: Rewriting queries to make them more efficient by reducing the number of operations or utilizing indexes.

• Caching: Storing frequently accessed data in memory to reduce the need for repeated database queries.

• Code refactoring: Restructuring code to improve efficienc...read more

IBM MQ is a messaging middleware that enables communication between applications using messages.

• IBM MQ is a reliable and secure messaging solution

• It supports various messaging patterns like point-to-point and publish/subscribe

• IBM MQ can be configured in Java code using the MQ classes for Java API

• Configuration involves setting up connection factories, queues, and channels

• Example: Configuring IBM MQ in Java code involves creating a connection factory, setting properties like ho...read more

Yes, parallel execution is possible in microservices.

• Microservices architecture allows for independent deployment and scaling of services.

• Each microservice can be executed in parallel, enabling concurrent processing.

• Parallel execution improves performance and scalability of the overall system.

• Microservices can communicate asynchronously, further enhancing parallelism.

• Examples of parallel execution in microservices include processing multiple requests simultaneously and execut...read more

Microservices is an architectural style where an application is composed of small, independent services that communicate with each other.

• Microservices are independently deployable and scalable.

• Each microservice performs a specific business function.

• Communication between microservices is usually through APIs.

• Microservices can be developed using different programming languages and technologies.

• Examples of companies using microservices include Netflix, Amazon, and Uber.

Questions related to database concepts and work experience.

• Views are virtual tables while MVs are physical tables that store the result of a query.

• Rank assigns a unique rank to each row while dense_rank assigns the same rank to rows with the same value.

• Functions return a value while procedures do not. Private functions are only accessible within the package they are defined in.

• Discussed my previous work experience and responsibilities.

var, let & const are JavaScript keywords used for declaring variables with different scoping rules.

• var has function scope and can be redeclared and updated

• let has block scope and can be updated but not redeclared

• const has block scope and cannot be updated or redeclared

• Use const for values that won't change, let for values that will change, and var for legacy code

• Example: var x = 10; let y = 'hello'; const z = true;

SQL is a standard language for managing relational databases, while PLSQL is Oracle's proprietary extension for SQL with procedural capabilities.

• SQL is a standard language used to manage and manipulate data in relational databases.

• PLSQL is Oracle's proprietary extension to SQL that adds procedural capabilities.

• SQL is used for querying and updating data, while PLSQL is used for writing procedural code like functions and stored procedures.

• SQL is a declarative language, while PL...read more

Node.js was chosen for its event-driven, non-blocking I/O model and scalability.

• Node.js is well-suited for real-time applications that require high concurrency and low latency.

• Java is better suited for large-scale enterprise applications that require strict type checking and robust error handling.

• Node.js has a large and active community with many useful libraries and frameworks.

• Node.js is lightweight and easy to deploy, making it a good choice for microservices architecture.

• N...read more

Web API requests in ASP.NET Core are processed through middleware in the request pipeline.

• Web API requests are processed through middleware components in the ASP.NET Core pipeline.

• Each middleware component can inspect, modify, or pass on the request to the next component.

• Middleware components can perform tasks such as authentication, logging, routing, and error handling.

• The request pipeline is configured in the Startup class using the Configure method.

Job scheduler is a tool that automates the execution of tasks at specified times or events.

• Job scheduler helps in automating repetitive tasks

• It can be used for scheduling backups, sending emails, running scripts, etc.

• Examples of job schedulers include Cron, Windows Task Scheduler, and Jenkins

• Job scheduler can improve efficiency and reduce errors in task execution

A code migration tool is used to transfer code from one platform to another.

• Code migration tools automate the process of transferring code from one platform to another.

• They can be used to migrate code between different programming languages or frameworks.

• Examples of code migration tools include Apache's Ant, Microsoft's Visual Studio, and JetBrains' ReSharper.

• Code migration tools can help save time and reduce errors when transferring code.

• They can also help ensure that the mi...read more

PCF stands for Pivotal Cloud Foundry. It is a cloud-native platform for deploying and managing applications.

• PCF is a popular choice for cloud application development and deployment.

• It provides a platform for developers to build, test, and deploy applications quickly and easily.

• PCF offers a range of features such as automatic scaling, load balancing, and self-healing.

• It supports multiple programming languages and frameworks, including Java, .NET, and Node.js.

• PCF is preferred t...read more

HTTP verbs are used to specify the type of action to be performed on a resource.

• GET - retrieve information from the server

• POST - submit data to be processed by the server

• PUT - update a resource on the server

• DELETE - delete a resource on the server

• HEAD - retrieve headers from the server

• OPTIONS - retrieve the supported HTTP methods for a resource

• PATCH - update a resource partially on the server

To deploy an application in cloud, follow these steps:

• Choose a cloud provider (Azure/AWS)

• Create an account and login to the cloud console

• Create a virtual machine or container to host the application

• Upload the application code and necessary dependencies

• Configure the application settings and environment variables

• Test the application and make necessary adjustments

• Deploy the application to the cloud

• Monitor the application performance and usage

BehaviorSubject is a type of subject in RxJS that emits the most recent value to its subscribers.

• BehaviorSubject is a type of subject in RxJS

• It emits the most recent value to its subscribers

• It requires an initial value upon creation

• It can be used to share state between components

• Example: const subject = new BehaviorSubject('initial value')

• Example: subject.subscribe(value => console.log(value))

• Example: subject.next('new value')

I was responsible for coordinating project activities, managing timelines, and ensuring deliverables were met.

• Coordinated project activities among team members

• Managed project timelines and deadlines

• Ensured project deliverables were met on time and within budget

Login activities in app are managed by implementing secure authentication methods and tracking user login/logout events.

• Implement secure authentication methods such as OAuth, JWT, or biometric authentication

• Track user login/logout events to monitor user activity and detect any suspicious behavior

• Use session management to control user access and prevent unauthorized login attempts

Azure offers a wide range of services including computing, storage, databases, networking, analytics, AI, IoT, and more.

• Compute services (Virtual Machines, App Services)

• Storage services (Blob Storage, File Storage)

• Database services (SQL Database, Cosmos DB)

• Networking services (Virtual Network, Load Balancer)

• Analytics services (Azure Data Lake, HDInsight)

• AI services (Cognitive Services, Machine Learning)

• IoT services (IoT Hub, Event Hubs)

Exception filters in Asp.net MVC are used to handle exceptions globally in the application.

• Exception filters are attributes that can be applied to controller actions or globally to handle exceptions.

• They are executed when an unhandled exception occurs during the execution of an action method.

• Exception filters can be used to log exceptions, redirect to error pages, or perform any custom action.

• Example: [HandleError] attribute can be used as an exception filter to handle except...read more

package.json is a file used in Node.js projects to manage dependencies and configuration.

• Contains metadata about the project such as name, version, and dependencies

• Used by package managers like npm to install and manage dependencies

• Can include scripts to automate tasks like testing and building

• Example: {"name": "my-project", "version": "1.0.0", "dependencies": {"express": "^4.17.1"}}

Production in a company involves the process of converting raw materials or components into finished goods or services.

• Planning and scheduling production activities

• Procuring raw materials or components

• Manufacturing or assembling products

• Quality control and assurance

• Packaging and labeling

• Distribution and logistics

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

• Spring Boot eliminates the need for manual configuration by providing default settings and auto-configuration.

• It reduces the development time and effort required to set up a Spring application.

• Spring Boot includes embedded servers like Tomcat, Jetty, and Undertow, making it easier to deploy standalone Spring applications.

• It offers a variety of...read more

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

• Design patterns help in creating maintainable, scalable, and reusable code.

• Examples of design patterns in Java include Singleton, Factory, Observer, and Strategy.

• They provide a general solution that can be adapted to various scenarios.

• Design patterns promote best practices and improve code readability.

Tokenisation in MDM is the process of replacing sensitive data with unique identifiers.

• Tokenisation helps in securing sensitive data by replacing it with a unique identifier or token.

• The token can be used for data processing and analysis without exposing the original data.

• For example, credit card numbers can be tokenised to protect them from theft or misuse.

• Tokenisation is different from encryption as it does not require a key to decrypt the data.

• Tokenisation can also help in...read more

Spread operator is a syntax in JavaScript that allows an iterable such as an array or string to be expanded into individual elements.

• It is denoted by three dots (...)

• It can be used to concatenate arrays

• It can be used to copy an array

• It can be used to pass arguments to a function

• It can be used to create a new object with properties of an existing object

• Example: const arr1 = [1, 2, 3]; const arr2 = [...arr1, 4, 5, 6];

• Example: const arr1 = [1, 2, 3]; const arr2 = [...arr1];

• Examp...read more

Types collection in PL/SQL is a collection type that can store multiple values of the same data type.

• Types collection can be nested tables, varrays, or associative arrays.

• Nested tables are like one-dimensional arrays with no upper bounds.

• Varrays are like arrays with a maximum size that is specified at declaration.

• Associative arrays are like arrays indexed by a key value.

Yes, a class can be converted to a list.

• A class can be converted to a list using the built-in list() function.

• The resulting list will contain all the attributes of the class.

• This can be useful for debugging or for iterating over the attributes of the class.

A session is a server-side storage of user data that is unique to each user, while a cookie is a client-side storage of user data that is stored on the user's browser.

• Session data is stored on the server, while cookie data is stored on the client's browser.

• Sessions are typically used for storing sensitive information like user authentication details, while cookies are often used for tracking user behavior or preferences.

• Sessions are temporary and expire when the user closes t...read more

API calls can be restricted by implementing rate limiting, authentication, and access control.

• Implement rate limiting to limit the number of requests per user or IP address.

• Use authentication to ensure only authorized users can access the API.

• Implement access control to restrict access to certain endpoints or resources.

• Use API keys to track usage and identify abusive behavior.

• Consider using a Content Delivery Network (CDN) to cache responses and reduce server load.

• Monitor API...read more

React lifecycle in functional components involves useEffect hook for side effects.

• UseEffect hook is used to perform side effects in functional components.

• It replaces lifecycle methods like componentDidMount, componentDidUpdate, and componentWillUnmount.

• UseEffect can be used to fetch data, subscribe to services, or update the DOM.

• Example: useEffect(() => { console.log('Component mounted'); }, []);

PLSQL Objects are user-defined data types in PL/SQL that encapsulate data and behavior.

• PLSQL Objects are created using the CREATE TYPE statement.

• They can have attributes (data) and methods (behavior).

• Objects can be instantiated and used in PL/SQL programs.

• Example: CREATE TYPE Person AS OBJECT (name VARCHAR2(50), age NUMBER);

AuthGuard and Interceptor are used in Angular for authentication and HTTP requests respectively.

• AuthGuard is used to protect routes from unauthorized access.

• Interceptor is used to modify HTTP requests and responses.

• AuthGuard can be used to redirect unauthorized users to a login page.

• Interceptor can be used to add headers or tokens to HTTP requests.

• Both can be used together to ensure authenticated users have access to protected routes.

Node.js architecture is based on event-driven, non-blocking I/O model.

• Node.js runs on V8 JavaScript engine

• It uses an event-driven architecture to handle asynchronous operations

• Node.js has a single-threaded event loop that allows for handling multiple connections simultaneously

• Modules in Node.js help in organizing code and promoting reusability

OOPs concept in Java stands for Object-Oriented Programming, which is a programming paradigm based on the concept of objects.

• OOPs focuses on creating objects that contain data and methods to manipulate that data.

• It involves concepts like inheritance, encapsulation, polymorphism, and abstraction.

• In Java, classes and objects are used to implement OOPs concepts.

• Example: Creating a class 'Car' with properties like 'brand' and 'color', and methods like 'drive' and 'stop'.

React is a library for building UI components while Angular is a full-fledged framework for building web applications.

• React uses a virtual DOM while Angular uses a real DOM

• React is more lightweight and flexible while Angular is more opinionated

• React uses JSX syntax while Angular uses HTML templates

• React has a larger ecosystem of third-party libraries while Angular has more built-in features

• React is easier to learn for beginners while Angular has a steeper learning curve

Hoisting is a JavaScript mechanism where variables and function declarations are moved to the top of their scope.

• Variables declared with var are hoisted to the top of their scope.

• Function declarations are also hoisted to the top of their scope.

• Function expressions are not hoisted.

• Hoisting can lead to unexpected behavior and bugs in code.

• Example: console.log(x); var x = 5; // Output: undefined

Implementing async await in a program

• Use async keyword before a function to make it asynchronous

• Use await keyword before a promise to pause execution until the promise is resolved

• Handle errors using try-catch blocks

Closure is a feature in programming languages that allows a function to access variables outside its scope.

• Closure is used to create private variables and methods in object-oriented programming.

• It is also used to create callbacks and event handlers in JavaScript.

• A closure is created when a function is defined inside another function and the inner function references variables from the outer function.

• The outer function can then return the inner function, which retains access t...read more

Paging is a technique used to divide large data sets into smaller chunks. Lazy loading is a technique used to load data on demand.

• Paging is used to improve performance by reducing the amount of data loaded into memory at once.

• Lazy loading is used to improve performance by only loading data when it is needed.

• Paging is commonly used in web applications to display large amounts of data in a user-friendly way.

• Lazy loading is commonly used in web applications to improve page load ...read more

Basic C# concepts include data types, variables, loops, conditional statements, classes, and methods.

• Data types in C# include int, string, bool, double, etc.

• Variables are used to store data and can be declared using var keyword.

• Loops like for, while, and do-while are used for repetitive tasks.

• Conditional statements like if-else and switch-case help in decision making.

• Classes are used to define objects with properties and methods.

• Methods contain code that performs specific tas...read more

Event loop is a mechanism in programming that allows for asynchronous execution of code by continuously checking for and executing tasks in a queue.

• Event loop is commonly used in JavaScript to handle asynchronous operations.

• It allows for non-blocking I/O operations by delegating tasks to the operating system.

• Event loop continuously checks the call stack and task queue to determine which tasks to execute next.

• Example: setTimeout() function in JavaScript uses event loop to exec...read more

Dependency injection is a design pattern in which components are given their dependencies rather than creating them internally.

• Allows for easier testing by mocking dependencies

• Promotes loose coupling between components

• Improves code reusability and maintainability

• Commonly used in frameworks like Spring in Java

Webdriver Interface is a programming interface that allows interaction with web browsers.

• It is a part of Selenium framework

• It provides methods to interact with web elements

• It can simulate user actions like clicking, typing, etc.

• It can handle alerts, frames, and windows

• It supports multiple programming languages like Java, Python, etc.

ConcurrentHashMap is a thread-safe implementation of the Map interface in Java.

• ConcurrentHashMap allows multiple threads to read and write to the map concurrently without the need for external synchronization.

• It achieves thread-safety by dividing the map into segments, each of which can be locked independently.

• ConcurrentHashMap is more efficient than using synchronized collections for concurrent access.

• Example: ConcurrentHashMap map = new ConcurrentHashMap<>();

Error is a compile-time issue while exception is a runtime issue in programming.

• Error is a compile-time issue detected by the compiler.

• Exception is a runtime issue that disrupts the normal flow of a program.

• Errors are generally caused by the environment in which the application is running.

• Exceptions are typically caused by the application itself.

• Example: Syntax error is an error, while NullPointerException is an exception.

Authentication in web API is the process of verifying the identity of a user or system before granting access to resources.

• Authentication involves validating the credentials provided by the user, such as username and password.

• Common authentication methods include token-based authentication, OAuth, and JWT.

• Authentication helps in ensuring that only authorized users can access protected resources.

• Examples of authentication in web APIs include using API keys, OAuth tokens, and u...read more

Dayaweave code for array sorting

• Use the sort() method to sort the array of strings alphabetically

• You can also use a custom compare function for sorting based on specific criteria

• Remember that sort() method modifies the original array

Node.js architecture is based on event-driven, non-blocking I/O model, with a single-threaded event loop.

• Node.js uses V8 JavaScript engine for executing code.

• It has a built-in module system for loading external modules.

• Node.js applications are typically run on a server, handling multiple client requests concurrently.

• It allows for real-time communication through WebSockets or other protocols.

• Node.js can be used for building APIs, web servers, microservices, and more.

Virtual DOM is a lightweight copy of the actual DOM in memory, used for efficient updating of the real DOM.

• Virtual DOM is a concept used in frameworks like React to improve performance by minimizing actual DOM manipulations.

• Changes are first made to the Virtual DOM, which is then compared to the real DOM to identify the minimal updates needed.

• This approach reduces the number of costly DOM operations, resulting in faster rendering and better user experience.

The question is asking for an explanation of 'what' something is and 'how' it works.

• Define the subject or concept being asked about

• Explain the characteristics or components of the subject

• Describe the process or mechanism of how it functions

• Provide examples to illustrate the explanation

Teradata is a traditional data warehouse system, while Snowflake is a cloud-based data warehouse platform.

• Teradata is an on-premise data warehouse solution known for its scalability and performance.

• Snowflake is a cloud-based data warehouse platform that offers flexibility and scalability.

• Teradata uses a shared-nothing architecture, while Snowflake uses a multi-cluster, shared data architecture.

• Snowflake separates storage and compute, allowing for independent scaling of each.

• T...read more