51 Spring Boot Interview Questions And Answers 2024

1.  What is Spring Boot?

2. How to create Spring Boot project in eclipse?

3. How to deploy spring boot application in tomcat?

4. What is the difference between Spring and Spring Boot?

5. What is actuator in spring boot?

6. How to change port in spring boot?

7. How to create war file in spring boot?

8. What is JPA in spring boot?

9. How to save image in database using spring boot?

10. What is auto configuration in spring boot?

11. How to resolve whitelabel error page in spring boot application?

12. How to fetch data from database in spring boot?

13. How to use logger in spring boot?

14. What is bootstrapping in spring boot?

15. How to create jar file in spring boot?

16. What is dependency injection in spring boot?

17. How to store image in MongoDB using spring boot?

18. How to configure hibernate in spring boot?

19. Mention the advantages of Spring Boot.

20. Explain what is thyme leaf and how to use thymeleaf?

21. What is the need for Spring Boot DevTools?

22. Can we change the port of the embedded Tomcat server in Spring boot?

23. Mention the steps to connect Spring Boot application to a database using JDBC

24. What are the @RequestMapping and @RestController annotation in Spring Boot used for?

25. What do you understand  by auto-configuration in Spring Boot and how to disable the auto-configuration?

26. Can you give an example for ReadOnly as true in Transaction management?

27. Mention the advantages of the YAML file than Properties file and the different ways to load  

28. What do you understand by Spring Data REST?

29. What do you think is the need for Profiles?

30. How to insert data in mysql using spring boot?

31. How to create a login page in spring boot?

32. What is the main class in spring boot?

33. How to use crud repository in spring boot?

34. How to run spring-boot jar from the command line?

35. What is Spring Boot CLI and how to execute the Spring Boot project using boot CLI?

36. what is the rest controller in spring boot?

37. How to handle 404 error in spring boot?

38. Which is the spring boot latest version?

39. How to check the environment properties in your Spring boot application?

40. Where do we define properties in the Spring Boot application?

41. What is an IOC container?

42. What are the basic Annotations that spring boot offers?

43. What is spring Boot dependency Management?

44. Can we create a non-web application in spring boot?

45. What is the default port of the tomcat server in Spring Boot?

46. Can we override or replace the embedded tomcat server in spring boot?

47. Can we disable the default web server in the spring boot application?

48. Explain @Restcontroller annotation in spring boot?

49. What is the difference between @RestController and @Controller in Spring Boot?

50. Describe the flow of HTTPS request through the spring boot app?

51. What is the difference between RequestMapping and GetMapping?

Spring Boot Interview Questions And Answers

1. Spring Boot:
   Ans. Spring Boot is an extension of the Spring framework that simplifies the process of building production-ready applications with the Spring framework. It provides a set of conventions and defaults for commonly used configurations, reducing the need for manual setup. Spring Boot is particularly well-suited for microservices and standalone applications.
2. Creating Spring Boot Project in Eclipse:
   Ans.You can create a Spring Boot project in Eclipse using the following steps:

• Open Eclipse and go to File -> New -> Spring Starter Project.
• Enter the project details, including the Group and Artifact names.
• Select the dependencies you want to include (e.g., Spring Web, Thymeleaf, etc.).
• Click “Finish” to create the project.

3.Deploying Spring Boot Application in Tomcat:

Ans.Spring Boot applications are typically packaged as JAR files and can be run using an embedded server. However, if you want to deploy a Spring Boot application in an external Tomcat server:

• Change the packaging in your pom.xml to <packaging>war</packaging>.
• Exclude the embedded Tomcat dependency.
• Build the WAR file and deploy it to Tomcat.

4.Difference Between Spring and Spring Boot:

Ans.Spring is a comprehensive framework for Java development, covering various aspects such as dependency injection, aspect-oriented programming, data access, and more.Spring Boot is a project within the Spring ecosystem that simplifies the configuration and deployment of Spring applications, providing a convention-over-configuration approach.

5.Actuator in Spring Boot:

Ans.
Spring Boot Actuator is a set of production-ready features that help you monitor and manage your application. It includes built-in endpoints for health checks, application info, environment properties, and more. Actuator provides useful insights into the application’s runtime behavior.

6.Changing Port in Spring Boot:

Ans.You can change the port in a Spring Boot application by adding a property in the application.properties or application.yml file:

   server.port=8081

7.Creating WAR File in Spring Boot:
Ans. To create a WAR file in Spring Boot:

• Change the packaging in your pom.xml to <packaging>war</packaging>.
• Exclude the embedded Tomcat dependency.
• Build the WAR file using mvn clean package.

8.JPA in Spring Boot:
Ans. JPA in a Nutshell:

JPA, or Java Persistence API, simplifies connecting your Java app to a database. It’s like a language translator between your Java code and the database. With JPA, you describe how your Java objects relate to database tables, and JPA handles the behind-the-scenes work of making them talk to each other. It’s a convenient tool that streamlines the process of dealing with databases in Java applications.

9.Saving Image in Database Using Spring Boot:

Ans.To save an image in a database using Spring Boot, you can follow these general steps:

• Define an entity class with a field of type byte[] to store the image data.
• Use appropriate annotations (e.g., @Lob) to map the field.
• Handle image upload in your controller and convert the uploaded file to a byte array.
• Save the byte array to the database using a JPA repository. Example entity class:

   @Entity
   public class ImageEntity {
       @Id
       @GeneratedValue(strategy = GenerationType.IDENTITY)
       private Long id;

       @Lob
       private byte[] imageData;

       // Getters and setters
   }

10. What is auto configuration in spring boot?

Ans. In Spring Boot, autoconfiguration is like a helpful assistant that sets up important things for your application without you having to tell it explicitly. It looks at what tools or libraries your project is using and automatically configures the necessary parts.

Annotation Use:

• Spring Boot uses an annotation called @EnableAutoConfiguration to do this