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1. How do you handle performance optimization in a web application?

Answer: I use lazy loading for images, minify CSS and JavaScript files, leverage browser caching, and implement CDNs (Content Delivery Networks) to reduce load times. I also optimize SQL queries, implement pagination for large datasets, and use efficient algorithms to minimize computation time.

2. Can you explain the concept of RESTful APIs?

Answer: RESTful APIs are a set of architectural principles used to design networked applications. They use standard HTTP methods (GET, POST, PUT, DELETE) and follow stateless interactions between the client and server. REST APIs return responses typically in JSON or XML format.

3. What is your experience with Java frameworks?

Answer: I have hands-on experience with Spring Boot for building microservices and Spring MVC for web development. I’ve also worked with Hibernate for ORM, which simplifies database interactions. These frameworks help streamline development, reduce boilerplate code, and enhance application scalability.

4. What is a Singleton pattern, and when would you use it?

Answer: A Singleton pattern ensures that a class has only one instance and provides a global point of access to it. It’s used in situations where a single object is required to coordinate actions across the system, such as in logging, configuration management, or database connections.

5. How does garbage collection work in Java?

Answer: In Java, garbage collection automatically reclaims memory by deleting objects that are no longer referenced. Java uses various GC algorithms like Mark and Sweep and Generational GC, running periodically to free up memory and optimize performance.

6. What is the difference between multithreading and multiprocessing?

Answer: Multithreading refers to executing multiple threads within a single process, allowing concurrent execution of tasks within the same application. Multiprocessing, on the other hand, involves running multiple processes, each with its own memory space, and is used to take advantage of multiple CPU cores.

7. Can you explain what dependency injection is in Spring?

Answer: Dependency Injection (DI) is a design pattern used in Spring to decouple object creation from its usage. Spring manages dependencies by injecting them at runtime using constructor injection, setter injection, or field injection. This promotes loose coupling and easier testing.

8. What is asynchronous programming and when should you use it?

Answer: Asynchronous programming allows a program to perform non-blocking operations, such as network calls or file I/O, by running tasks in the background. It is used to improve application responsiveness, particularly in applications that require real-time data updates or high concurrency.

9. Explain the concept of ORM (Object Relational Mapping).

Answer: ORM is a technique that allows developers to interact with a database using objects in their programming language. Frameworks like Hibernate map object-oriented models to relational databases, abstracting away SQL queries and enabling developers to focus more on business logic.

10. How would you implement security in a web application?

Answer: I implement security using techniques like input validation, sanitization, and protection against SQL injection and XSS (Cross-Site Scripting) attacks. I also use SSL/TLS encryption, OAuth for authentication, and JWT tokens for secure, stateless sessions.

11. What is a Microservice Architecture?

Answer: Microservice architecture is a style of software architecture where an application is divided into small, independently deployable services. Each service focuses on a specific business function and communicates with others via APIs. This approach improves scalability, fault tolerance, and ease of deployment.

12. How do you manage version control in a collaborative project?

Answer: I use Git for version control, and I follow branching strategies like Git Flow or Feature Branching to manage changes efficiently. Regular commits, clear commit messages, and pull requests ensure seamless collaboration among team members.

13. Explain Docker and how you use it in development.

Answer: Docker is a containerization platform that allows developers to package applications with all dependencies into a single unit, ensuring consistency across development, testing, and production environments. I use Docker for setting up lightweight, isolated environments, making it easy to deploy and scale applications.

14. What are SQL Joins, and how are they used?

Answer: SQL Joins are used to combine rows from two or more tables based on related columns. Types include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN. They are commonly used to retrieve related data across multiple tables in a relational database.