What is Spring Boot?

Spring Boot is an open-source framework designed to simplify the development of production-ready, stand-alone, and web-based applications using the Spring Framework.

What are the key features of Spring Boot?

Key features include auto-configuration, standalone Spring applications, production-ready defaults, and a wide range of built-in tools for development.

How does Spring Boot simplify the development process?

Spring Boot simplifies development by providing defaults for application setups and reducing the need for manual configuration. It also comes with a range of built-in tools for tasks like packaging, monitoring, and testing.

What is the purpose of the Spring Boot Starter POMs?

Spring Boot Starter POMs are a set of dependency descriptors that simplify the inclusion of dependencies in the project. They provide a convenient way to declare dependencies based on the type of project (web, data, messaging, etc.).

How does Spring Boot support microservices architecture?

Spring Boot provides features like embedded containers, Spring Cloud for distributed systems, and Spring Boot Actuator for monitoring, making it well-suited for microservices development.

Explain the concept of auto-configuration in Spring Boot.

Auto-configuration in Spring Boot automatically configures the application based on the project’s dependencies. It helps in minimizing manual configuration and speeds up the development process.

What is the significance of the @SpringBootApplication annotation?

The @SpringBootApplication annotation is a meta-annotation that combines @Configuration, @EnableAutoConfiguration, and @ComponentScan. It marks the main class as a configuration class, enables auto-configuration, and triggers component scanning.

How does Spring Boot support externalized configuration?

Spring Boot supports externalized configuration through properties files, YAML files, environment variables, and command-line arguments. It allows developers to configure applications without modifying the code.

Explain the purpose of the Spring Boot Actuator.

Spring Boot Actuator provides production-ready features like health checks, metrics, application information, and more. It is useful for monitoring and managing Spring Boot applications in a production environment.

What is the significance of the application.properties file in Spring Boot?

The application.properties file is used for configuring Spring Boot applications. It allows developers to define properties such as database configurations, server ports, and other settings.

How can you override the default configuration in Spring Boot?

Default configuration in Spring Boot can be overridden by providing custom properties in the application.properties or application.yml files. Additionally, command-line arguments and environment variables can be used for customization.

Explain the purpose of the SpringApplication class.

The SpringApplication class is the main entry point for a Spring Boot application. It is responsible for bootstrapping the application, loading the application context, and starting the embedded web server.

What is the role of Spring Boot Starters in dependency management?

Spring Boot Starters simplify dependency management by providing pre-configured sets of dependencies for various types of applications. They help in including relevant dependencies with minimal effort.

How does Spring Boot handle database transactions?

Spring Boot leverages the Spring Data JPA module for handling database transactions. It provides annotations like @Transactional to manage transactions declaratively.

Explain the purpose of the Spring Boot DevTools.

Spring Boot DevTools is a set of tools aimed at improving the development experience. It provides features like automatic application restart, remote application configuration, and enhanced reloading of templates.

How can you create a RESTful API in Spring Boot?

You can create a RESTful API in Spring Boot by using the @RestController annotation on a class and the @RequestMapping or @GetMapping annotations on methods. Spring Boot provides features for easily building RESTful services.

What is Spring Boot Auto-Configuration and how does it work?

Spring Boot Auto-Configuration automatically configures the application based on the project’s dependencies. It uses classpath scanning to detect available configurations and applies them without explicit user configuration.

How does Spring Boot support testing?

Spring Boot provides testing support through the @SpringBootTest annotation for integration tests and the @MockBean annotation for creating mock beans. It also includes testing utilities for testing web applications and components.

What is the role of Spring Boot Starter Web in web development?

Spring Boot Starter Web is a starter POM that includes dependencies for building web applications. It provides defaults for setting up a web project, including an embedded web server and Spring MVC.

Explain the difference between Spring Boot and Spring.

Spring Boot is a framework built on top of the Spring Framework. While the Spring Framework provides comprehensive infrastructure support, Spring Boot focuses on convention over configuration, simplifying development, and providing production-ready defaults.

How does Spring Boot support caching?

Spring Boot supports caching through the @Cacheable and related annotations. It integrates with caching providers like Ehcache, Hazelcast, and others to improve application performance.

What is the purpose of the CommandLineRunner interface in Spring Boot?

The CommandLineRunner interface in Spring Boot allows developers to run specific code after the application context has been loaded fully. It is useful for performing initialization tasks.

How can you create a Spring Boot project using Spring Initializr?

You can create a Spring Boot project using Spring Initializr by visiting the website (start.spring.io), selecting project options, adding dependencies, and generating the project. The downloaded project can then be imported into an IDE.

How does Spring Boot handle security?

Spring Boot provides security features through the Spring Security module. Developers can configure security settings using annotations and leverage built-in authentication and authorization mechanisms.

What is the purpose of the @RestControllerAdvice annotation in Spring Boot?

The @RestControllerAdvice annotation is used to define global exception handling for all @RestController classes. It allows developers to centralize exception handling logic in one place.

Explain the concept of Spring Boot Actuator endpoints.

Spring Boot Actuator endpoints expose runtime information about the application. Examples include health checks, metrics, environment details, and more. These endpoints are useful for monitoring and management.

How does Spring Boot support internationalization and localization?

Spring Boot supports internationalization and localization through the use of message properties files. Developers can define messages for different locales, and Spring Boot automatically selects the appropriate messages based on the user’s locale.

What is Spring Boot Data JPA?

Spring Boot Data JPA is a module that simplifies the development of data access layer in Spring applications. It builds on the Spring Data project and provides a set of abstractions for working with relational databases using JPA.

How can you deploy a Spring Boot application?

Spring Boot applications can be deployed in various ways, including as standalone JAR files, WAR files in servlet containers, or as part of a cloud-native deployment using platforms like Docker and Kubernetes.

What is the role of Spring Boot Actuator health checks?

Spring Boot Actuator health checks provide information about the application’s health status. They can be used for monitoring and are often utilized by external tools to assess the overall health of the application.

How does Spring Boot support asynchronous programming?

Spring Boot supports asynchronous programming using the @Async annotation and the CompletableFuture class. It allows developers to execute methods asynchronously, improving application performance.

What is the purpose of the @SpringBootTest annotation?

The @SpringBootTest annotation is used for integration testing in Spring Boot. It loads the entire application context and allows developers to test the application in a way that closely resembles its runtime behavior.

How does Spring Boot handle properties and configuration files?

Spring Boot allows developers to configure applications using properties files (application.properties or application.yml). It supports hierarchical configurations, and properties can be overridden based on the environment.

What is the significance of the @ComponentScan annotation in Spring Boot?

The @ComponentScan annotation is used to enable component scanning in Spring Boot. It specifies the base packages to scan for components, such as controllers, services, and repositories.

How does Spring Boot support creating RESTful services with Spring MVC?

Spring Boot simplifies the creation of RESTful services with Spring MVC by providing annotations like @RestController and @RequestMapping. It eliminates boilerplate code and simplifies the configuration of RESTful endpoints.

What is the purpose of the application.yml file in Spring Boot?

The application.yml file is an alternative to application.properties for configuring Spring Boot applications. It allows developers to use a YAML-based syntax for defining properties and configurations.

How can you customize error responses in a Spring Boot application?

Error responses in a Spring Boot application can be customized by creating a custom error controller and handling specific error scenarios. Additionally, the application.properties or application.yml file can be used to configure error-related properties.

What is the role of the @ConditionalOnProperty annotation in Spring Boot?

The @ConditionalOnProperty annotation in Spring Boot is used for conditional bean creation based on the presence or absence of specified properties. It allows developers to control the instantiation of beans based on configuration properties.

How does Spring Boot support the use of profiles?

Spring Boot supports the use of profiles to configure different sets of properties for different environments. Profiles can be activated using the spring.profiles.active property.

What is the purpose of the Spring Boot @Scheduled annotation?

The @Scheduled annotation is used to define scheduled tasks in Spring Boot. It allows developers to execute methods at fixed intervals or based on cron expressions.

How does Spring Boot handle dependency injection?

Spring Boot uses the core Spring Framework’s dependency injection mechanism. It allows developers to inject dependencies using annotations like @Autowired and constructor injection.

What is the Spring Boot Actuator Loggers endpoint used for?

The Loggers endpoint in Spring Boot Actuator allows developers to view and modify the logging configuration at runtime. It is useful for adjusting log levels and managing logging for different components.

How can you configure a database connection in a Spring Boot application?

Database connections in a Spring Boot application can be configured using properties in the application.properties or application.yml file. Developers can specify details such as database URL, username, password, and driver class.

What is the purpose of the Spring Boot @RequestBody annotation?

The @RequestBody annotation is used in Spring Boot to bind the request body to a method parameter in a controller. It is commonly used in RESTful services to handle incoming data in the request body.

How does Spring Boot handle exception handling in RESTful services?

Spring Boot provides mechanisms for handling exceptions in RESTful services, such as the @ExceptionHandler annotation for specific exception types and global exception handling using @ControllerAdvice.

What is the purpose of the Spring Boot @EnableCaching annotation?

The @EnableCaching annotation is used to enable caching in a Spring Boot application. It allows developers to cache method results, improving performance by avoiding redundant computations.

How does Spring Boot support the creation of WebSocket applications?

Spring Boot provides support for creating WebSocket applications using the @EnableWebSocket annotation and WebSocket-related classes. It simplifies the configuration and development of real-time, bidirectional communication.

What is the significance of the Spring Boot @Transactional annotation?

The @Transactional annotation in Spring Boot is used to define the scope of a transaction. It ensures that a series of operations are executed as a single transaction, and any failure results in a rollback.

How does Spring Boot handle static resources, such as HTML and CSS files?

Spring Boot automatically configures static resource handling, allowing developers to place static files (HTML, CSS, etc.) in specific directories. These resources are served directly by the embedded web server.

How can you enable Cross-Origin Resource Sharing (CORS) in a Spring Boot application?

CORS in a Spring Boot application can be enabled using the @CrossOrigin annotation on controllers or by configuring CORS globally using properties in the application.properties or application.yml file.