Spring Boot Interview Questions

1.      What is Spring Boot?

Spring Boot is a framework that allows developers to easily build production-ready Spring applications. It provides a set of conventions and sensible defaults that allow developers to quickly get started with building their applications.

2.      What are the key features of Spring Boot?

The key features of Spring Boot include automatic configuration, starter dependencies, and the ability to run applications as standalone Java applications.

3.      How does Spring Boot simplify the development of a Spring application?

Spring Boot simplifies the development of a Spring application by providing a set of conventions and sensible defaults, as well as providing a number of starter dependencies that can be easily included in a project. This allows developers to quickly get started with building their applications and reduces the amount of configuration required.

4.      How does Spring Boot handle configuration?

Spring Boot handles configuration by automatically configuring Spring and the application based on the presence of certain classes and properties on the classpath. Developers can also provide their own configuration through application.properties or application.yml files, or through command-line arguments.

5.      How does Spring Boot handle security?

Spring Boot provides a number of features to handle security, such as automatic configuration of Spring Security and support for OAuth 2.0 and JWT. Developers can also provide their own security configuration through properties files or Java configuration.

6.      What is the difference between Spring Boot and Spring MVC?

Spring Boot is a framework for building Spring applications, while Spring MVC is a module of the Spring Framework that provides a Model-View-Controller (MVC) architecture for building web applications. While Spring Boot provides a number of features to simplify the development of Spring applications, Spring MVC focuses specifically on building web applications.

7.      How does Spring Boot handle data access?

Spring Boot provides a number of features to handle data access, such as support for JDBC, JPA, and MongoDB out of the box. It also provides Spring Data, a module that makes it easy to implement data access repositories, with support for various data stores. It also provides auto-configuration for data source and entity manager.

8.      How does Spring Boot handle logging?

Spring Boot uses Logback as its default logging framework, but also supports other logging frameworks such as log4j2, and java.util.logging. It provides an automatic configuration of the logging system, and developers can also provide their own logging configuration through properties files or Java configuration.

9.      How does Spring Boot handle web services?

Spring Boot provides support for building web services through Spring Web MVC, Spring WebFlux, and Spring Data REST. It also provides support for various web service protocols such as REST, SOAP, and JSON-RPC.

10.   How does Spring Boot handle testing?

Spring Boot provides support for testing through the Spring Test module, which provides a number of features for unit testing and integration testing, such as support for JUnit, TestNG, and Mockito, as well as the ability to easily test Spring components and applications.

11.   How does Spring Boot handle deployment?

Spring Boot provides support for easy deployment through its ability to run as a standalone Java application, as well as support for packaging as a WAR file for deployment in a traditional application server. It also provides support for cloud-native deployment through Spring Cloud.

12.   How does Spring Boot handle monitoring and management?

Spring Boot provides a number of features for monitoring and management through the Spring Boot Actuator module, which provides endpoints for monitoring application health, metrics, and configuration. It also provides support for customizing and extending the Actuator functionality.

13.   What are the benefits of using Spring Boot?

Some benefits of using Spring Boot include ease of development, less configuration required, improved testability, and better monitoring and management capabilities. It also provides a high degree of flexibility, and it can be integrated with other Spring projects and third-party libraries.

14.   How can you create a Spring Boot application?

There are a few ways to create a Spring Boot application, including using the Spring Initializer website, using the Spring Boot CLI, or using an IDE with Spring Boot support such as Spring Tool Suite or IntelliJ IDEA.

15.   How can you customize the configuration of a Spring Boot application?

You can customize the configuration of a Spring Boot application by providing your own application.properties or application.yml file in the classpath, or by using command-line arguments. You can also use Java-based configuration or annotation-based configuration, which allows you to define the configuration in a Java class.

16.   How can you create a RESTful web service in Spring Boot?

You can create a RESTful web service in Spring Boot by creating a Spring MVC controller class and annotating it with the @RestController annotation. You can then add methods to the controller class that handle incoming HTTP requests and return appropriate HTTP responses.

17.   How can you create a SOAP web service in Spring Boot?

You can create a SOAP web service in Spring Boot by creating a Spring Web Service endpoint class and annotating it with the @Endpoint annotation. You can then add methods to the endpoint class that handle incoming SOAP requests and return appropriate SOAP responses.

18.   How can you create a web application in Spring Boot?

You can create a web application in Spring Boot by creating a Spring MVC controller class and annotating it with the @Controller annotation. You can then add methods to the controller class that handle incoming HTTP requests and return appropriate views. You can also use Spring Boot's built-in support for Thymeleaf or other template engines to easily create views.

19.   How can you create a scheduled task in Spring Boot?

You can create a scheduled task in Spring Boot by creating a method and annotating it with the @Scheduled annotation. This method will be invoked by Spring at the specified intervals.

20.   How can you create a database-backed application in Spring Boot?

You can create a database-backed application in Spring Boot by adding the Spring Data JPA starter to your project, and then creating JPA entities and repositories. Spring Boot will automatically configure a data source and entity manager, and you can use the repositories to interact with the database.

21.   How can you create a microservice in Spring Boot?

You can create a microservice in Spring Boot by creating a Spring Boot application and implementing the functionality of the service in a Spring component or controller. You can also use Spring Cloud to easily integrate your microservice with service discovery, load balancing, and other features commonly needed in a microservice architecture.

22.   How can you create a Spring Boot application with a user interface?

You can create a Spring Boot application with a user interface by including the Spring Boot Web starter in your project, and then adding views and controllers to handle incoming HTTP requests and return appropriate HTML or other markup. You can also use Spring Boot's built-in support for Thymeleaf or other template engines to easily create views.

23.   How can you create a Spring Boot application that consumes a RESTful web service?

You can create a Spring Boot application that consumes a RESTful web service by using the Spring RestTemplate class or the Spring WebClient class to make HTTP requests to the web service. You can also use the Spring Feign library which is a declarative web service client.

24.   How can you create a Spring Boot application that consumes a SOAP web service?

You can create a Spring Boot application that consumes a SOAP web service by using the Spring WebServiceTemplate class to send and receive SOAP messages. You can also use JAX-WS or Spring-WS to create SOAP client.

25.   How can you create a Spring Boot application that uses a database?

You can create a Spring Boot application that uses a database by including the Spring Boot Data JPA starter in your project and configuring the application to connect to a database. You can then use the Spring Data JPA repositories to interact with the database.

26.   How can you create a Spring Boot application that uses a messaging system?

You can create a Spring Boot application that uses a messaging system by including the Spring Boot Starter AMQP in your project and configuring the application to connect to a messaging system like RabbitMQ or Apache Kafka. You can then use the Spring AMQP or Spring Kafka to interact with the messaging system.

27.   How can you create a Spring Boot application that uses a cache?

You can create a Spring Boot application that uses a cache by including the Spring Boot Starter Cache in your project and configuring the application to use a caching provider like EhCache or Hazelcast. You can then use the Spring Cache abstraction to easily cache data in your application.

28.   How can you create a Spring Boot application that uses a NoSQL database?

You can create a Spring Boot application that uses a NoSQL database by including the Spring Boot Starter Data MongoDB or Spring Boot Starter Data Cassandra in your project and configuring the application to connect to a NoSQL database. You can then use the Spring Data repositories to interact with the NoSQL database.

29.   How can you create a Spring Boot application that uses a search engine?

You can create a Spring Boot application that uses a search engine by including the Spring Boot Starter Data Elasticsearch in your project and configuring the application to connect to an Elasticsearch cluster. You can then use the Spring Data Elasticsearch repositories to interact with the search engine.

30.   How does Spring Boot handle security?

Spring Boot provides a number of features to handle security, such as automatic configuration of Spring Security and support for OAuth 2.0 and JWT. Developers can also provide their own security configuration through properties files or Java configuration, and it also comes with a number of security best practices out of the box.

31.   How does Spring Boot handle exception handling?

Spring Boot provides a number of features to handle exception handling, such as the @ControllerAdvice annotation that allows developers to define a global exception handler for the application, and the @ExceptionHandler annotation that allows developers to define specific exception handlers for controllers.

32.   How does Spring Boot handle validation?

Spring Boot provides built-in support for bean validation using the javax.validation API, and it is easy to add validation to a Spring Boot application by annotating bean properties with validation constraints.

33.   How does Spring Boot handle internationalization (i18n)?

Spring Boot provides built-in support for internationalization (i18n) by using the standard Java ResourceBundle mechanism. Developers can define messages and properties files for different locales and Spring Boot will automatically pick the appropriate files based on the user's locale.

34.   How does Spring Boot handle access to the file system?

Spring Boot provides built-in support for accessing the file system through the standard Java I/O classes such as java.io.File and java.nio.file.Path. Additionally, Spring provides the Resource abstraction which makes it easy to work with resources such as files, URLs, and classpath resources.

35.   How does Spring Boot handle data encryption?

Spring Boot provides built-in support for data encryption through the Spring Security module. It provides a number of features such as password encoders, password hashing, and data encryption that can be easily configured and used in a Spring Boot application.

36.   How can you use Spring Boot with an existing application?

You can use Spring Boot with an existing application by adding the Spring Boot Starter parent POM to your project and including the appropriate Spring Boot starters for the features you want to use. You can also use the @EnableAutoConfiguration annotation to enable the automatic configuration of Spring Boot in your existing application.

37.   How can you use Spring Boot with a microservices architecture?

You can use Spring Boot with a microservices architecture by creating individual Spring Boot applications for each microservice, and then using Spring Cloud to easily integrate the microservices with service discovery, load balancing, and other features commonly needed in a microservices architecture.

38.   How does Spring Boot handle deployment?

Spring Boot provides support for easy deployment through its ability to run as a standalone Java application, as well as support for packaging as a WAR file for deployment in a traditional application server. It also provides support for cloud-native deployment through Spring Cloud.

39.   What is the Spring Boot Actuator?

The Spring Boot Actuator is a module of Spring Boot that provides a number of features for monitoring and managing a Spring Boot application, such as metrics, health checks, and configuration information. It provides a set of RESTful endpoints that can be accessed by developers to get information about the application.