Certainly! Here are 20 common Spring Boot interview questions along with their answers:
What is Spring Boot?
Spring Boot is an opinionated framework built on top of the Spring framework that simplifies the development of Java applications. It provides default configurations and conventions, reducing boilerplate code and enabling developers to quickly create production-ready applications.
What are the key features of Spring Boot?
Key features of Spring Boot include:
- Auto-configuration
- Embedded servers
- Starter dependencies
- Actuator
- Production-ready metrics and monitoring
- How does Spring Boot simplify the configuration of a Spring application?
- Spring Boot uses convention over configuration. It provides default configurations based on classpath settings, annotations, and properties files. Developers can override these defaults by providing their own configurations.
What is the difference between Spring and Spring Boot?
Spring is a comprehensive framework that provides various modules for developing enterprise Java applications. Spring Boot is built on top of the Spring framework and focuses on simplifying the configuration and development of Spring applications.
What is the purpose of the @SpringBootApplication annotation?
The @SpringBootApplication annotation is used to indicate the main class of a Spring Boot application. It combines the @Configuration, @EnableAutoConfiguration, and @ComponentScan annotations into a single annotation.
What is Spring Boot Starter?
A Spring Boot Starter is a dependency that includes a set of opinionated dependencies related to a specific feature or functionality. It simplifies dependency management and configuration for that specific feature.
What is the purpose of the application.properties (or application.yml) file in Spring Boot?
The application.properties or application.yml file is used to configure various settings of a Spring Boot application, such as server port, database connection details, logging configuration, etc.
What is the purpose of the Spring Boot Actuator?
Spring Boot Actuator provides production-ready features for monitoring and managing Spring Boot applications. It includes endpoints that expose useful information and metrics about the application, such as health checks, metrics, environment details, and more.
What is the difference between @RestController and @Controller?
The @RestController annotation is a specialized version of @Controller that combines @Controller and @ResponseBody. It is used to build RESTful web services, where the return values of methods are automatically serialized to JSON or XML.
Explain the concept of Spring Boot Auto-configuration.
Spring Boot Auto-configuration automatically configures the Spring application based on the dependencies and the classpath. It analyzes the project's dependencies and, if a specific library is found on the classpath, it automatically configures the necessary beans and settings.
What is the purpose of the @Autowired annotation?
The @Autowired annotation is used to automatically wire (inject) dependencies into a Spring bean. It can be applied to constructors, setter methods, or directly on fields.
What is the Spring Boot starter parent?
The Spring Boot starter parent is a special Maven POM that provides default configurations and dependency management for Spring Boot applications. It simplifies the project's Maven configuration by inheriting common settings.
How can you create a custom starter in Spring Boot?
To create a custom starter, you can follow these steps:
Create a Maven module with a specific naming convention (e.g., spring-boot-starter-{name}).
Define the necessary dependencies and configurations in the module.
Package the module as a JAR and distribute it