Spring Boot Interview Questions and Answers

This section covers frequently asked Spring Boot interview questions.

1. What is Spring Boot?

Spring Boot simplifies the development of stand-alone Spring-based applications. It reduces the amount of configuration needed, making it faster and easier to create Spring applications.

2. Advantages of Spring Boot.

• Creates stand-alone applications (runnable JAR files).
• Embeds servers (Tomcat, Jetty, Undertow).
• Simplifies Maven configuration using starter POMs.
• Auto-configuration for Spring.

3. Features of Spring Boot.

• Web development support
• SpringApplication class
• Application events and listeners
• Admin features (using Spring Boot Actuator)

4. Creating a Spring Boot Application with Maven.

Several methods exist to create Spring Boot projects, including using the Spring Initializr web tool, the Spring Starter Project wizard in IDEs, and the Spring Boot CLI (command-line interface).

5. Creating a Spring Boot Project with Spring Initializr.

(This section would provide steps for using the Spring Initializr online tool to generate a Spring Boot project.)

6. Creating a Spring Boot Project with Spring Boot CLI.

(This section would describe how to use the Spring Boot CLI for creating and managing Spring Boot projects.)

7. Creating a Simple Spring Boot Application.

(This section would outline the steps to create a basic Spring Boot application using an IDE like Spring Tool Suite (STS).)

8. Spring Boot Annotations (@RestController).

@RestController is a stereotype annotation combining @Controller and @ResponseBody. It's used to create REST controllers in Spring Boot applications.

9. Spring Boot Dependency Management.

Spring Boot simplifies dependency management by automatically resolving and configuring dependencies, eliminating the need for manual version specifications.

10. Spring Boot Properties.

Spring Boot properties (in application.properties or application.yml) configure various application settings.

11. Spring Boot Starters.

Starters are pre-configured dependency sets, simplifying project setup. For example, spring-boot-starter-web includes dependencies needed for creating web applications.

12. Spring Boot Actuator.

Spring Boot Actuator provides endpoints for monitoring and managing your application (health checks, metrics, etc.).

13. Thymeleaf.

Thymeleaf is a server-side templating engine often used with Spring Boot for creating dynamic web pages.

14. Using Thymeleaf.

Add the spring-boot-starter-thymeleaf dependency to your pom.xml file.

15. Connecting Spring Boot to a Database with JPA.

Use the spring-boot-starter-data-jpa starter.

16. Connecting Spring Boot to a Database with JDBC.

(This section would explain the steps to connect a Spring Boot application to a database using JDBC.)

17. @RestController Annotation (Repeated from earlier).

A convenience annotation for creating REST controllers that return data directly in the response body.

18. @RequestMapping Annotation.

@RequestMapping maps HTTP requests to specific handler methods in your Spring controllers. It defines the URL paths that trigger those methods.

19. Creating a Spring Boot Project with the Spring Starter Project Wizard.

(This section would describe the steps involved in using the Spring Starter Project wizard in an IDE like STS to create a Spring Boot application.)

20. Spring vs. Spring Boot.