Top most asked Spring Boot Questions in Interviews.

Spring Boot Essentials: A Comprehensive Guide

This guide provides answers to key questions about Spring Boot, a powerful framework for building stand-alone, production-grade Spring-based applications.

Core Spring Boot Concepts:

1. Spring Boot Features: Spring Boot simplifies Spring application development by providing auto-configuration, starter dependencies, and embedded servers, eliminating boilerplate code and configuration. It promotes convention over configuration.

2. Key Components: Core components include Spring Boot Starter dependencies, the @SpringBootApplication annotation, embedded servers (like Tomcat or Netty), Spring Data (for database interaction), and Spring MVC (for web applications).

3. Advantages of Spring Boot: Faster development, easier deployment (standalone JARs), improved productivity, reduced configuration, and better testing capabilities are key advantages.

4. Spring Boot Starter Dependencies: These dependencies simplify project setup by including all necessary libraries for specific functionalities (e.g., spring-boot-starter-web for web applications, spring-boot-starter-data-jpa for JPA).

5. Starting a Spring Application: The main method typically calls SpringApplication.run(), which bootstraps the application context.

6. @SpringBootApplication Annotation: This annotation combines @Configuration, @EnableAutoConfiguration, and @ComponentScan, enabling Spring Boot's core features.

7. Spring Initializr: A web-based tool that generates Spring Boot projects with pre-configured dependencies.

8. Spring Boot CLI: A command-line interface for creating and running Spring Boot applications. Common commands include create, run, and test.

9. JPA in Spring Boot: Java Persistence API (JPA) simplifies database interaction using annotations and interfaces. Spring Boot integrates seamlessly with JPA through frameworks like Hibernate.

10. Starters in Spring Boot: Starters are pre-packaged dependencies that simplify the inclusion of related libraries. They reduce the need for manual dependency management.

11. External Configuration Handling: Spring Boot supports various external configuration sources, including properties files (application.properties, application.yml), environment variables, and command-line arguments.

12. application.properties (or application.yml): This file contains application configuration properties. .yml offers a more structured, YAML-based configuration.

13. Auto-Configuration Mechanism: Spring Boot automatically configures beans based on the dependencies found in the classpath. It intelligently infers settings and avoids unnecessary configuration.

14. @Component Annotation: Marks a class as a Spring-managed bean, making it available for dependency injection.

15. Annotation Differences (@Component, @Repository, @Service, @Controller): These are stereotype annotations, specializing @Component. @Repository is for data access objects, @Service for business logic, and @Controller for web controllers.

16. Dependency Management: Spring Boot simplifies dependency management using a parent POM (Project Object Model) that manages versions and transitive dependencies.

17. @Autowired Annotation: Enables automatic dependency injection by type.

18. @Qualifier Annotation: Used with @Autowired to specify a bean when multiple beans of the same type exist.

19. SpringApplication.run() Method: The entry point for launching a Spring Boot application.

20. Spring Boot CLI (already defined above).

21. @RequestMapping Annotation: Maps HTTP requests to specific controller methods in Spring MVC.

22. Spring MVC vs. Spring Boot: Spring MVC is a web framework; Spring Boot is a framework that simplifies building Spring applications, including Spring MVC applications. Spring Boot builds on top of Spring MVC.

23. @RestController Annotation: Combines @Controller and @ResponseBody, indicating that the controller methods return data directly in the response body (e.g., JSON or XML).

24. @RestController vs. @Controller: @Controller renders views; @RestController returns data directly.

25. @PathVariable, @RequestBody, @RequestParam Annotations: These annotations are used in controller methods to handle different aspects of HTTP requests. @PathVariable extracts values from the URL path, @RequestBody reads the request body (often JSON), and @RequestParam gets parameters from the query string.

26. Database Support: Spring Boot simplifies database interaction through Spring Data JPA, JDBC, or other data access technologies.

27. @Entity Annotation: Marks a class as a JPA entity, representing a table in the database.

28. @GeneratedValue Annotation: Specifies how the primary key of an entity is generated (e.g., auto-increment).

29. @Id Annotation: Marks a field as the primary key of a JPA entity.

30. ResponseEntity: A class that encapsulates HTTP status codes and response bodies, providing more control over HTTP responses.

The above is the detailed content of Top most asked Spring Boot Questions in Interviews.. For more information, please follow other related articles on the PHP Chinese website!