As a seasoned Spring Boot developer with 10 years of experience, you can expect to be asked some challenging interview questions during the hiring process. While the questions will vary depending on the company, industry, and specific role you are applying for, there are certain key concepts and topics that are likely to come up. In this article, we will discuss some of the most common Spring Boot interview questions for 10 years experienced professionals.
- What is Spring Boot, and how does it differ from Spring Framework?
Spring Boot is an open-source Java-based framework used to create standalone, production-grade Spring-based applications with minimal configuration. It provides a set of pre-configured dependencies and auto-configuration modules that eliminate the need for boilerplate code, making it easier and faster to create applications. Spring Boot also integrates with other Spring Framework modules such as Spring Data, Spring MVC, and Spring Security.
The main difference between Spring Boot and Spring Framework is that Spring Boot is an opinionated framework that provides a streamlined way of developing Spring-based applications, while Spring Framework is a more traditional, modular framework that requires more configuration and setup.
- What are the advantages of using Spring Boot?
Spring Boot offers several advantages for developers, including:
- Rapid application development: Spring Boot eliminates the need for a lot of boilerplate code, allowing developers to focus on writing business logic.
- Production-ready: Spring Boot provides many pre-built components and features such as security, data access, and monitoring, making it easier to create production-grade applications.
- Microservices support: Spring Boot is an ideal framework for creating microservices-based architectures, thanks to its lightweight and modular design.
- Easy integration: Spring Boot provides integration with several other Spring modules and third-party libraries, allowing developers to easily add features to their applications.
- What is an embedded container in Spring Boot, and why is it important?
Spring Boot includes an embedded container, which is a lightweight server that can run inside a Spring Boot application. It eliminates the need for developers to deploy their applications on external containers like Tomcat or Jetty, making it easier to develop and deploy applications. The embedded container also supports hot reloading, which allows developers to make changes to their code and see the results immediately, without having to restart the application.
- How does Spring Boot handle database connections?
Spring Boot provides a set of auto-configuration modules that make it easy to connect to databases. By default, it supports several popular databases like MySQL, PostgreSQL, and MongoDB. Developers can specify the database they want to use in the application.properties or application.yml file, and Spring Boot will automatically configure the database connection.
- What is Spring Security, and how does it work?
Spring Security is a module of the Spring Framework that provides security features for Java-based applications. It offers authentication and authorization services for web and non-web applications. Spring Security uses a set of filters to intercept and process requests, and it supports several authentication mechanisms such as basic authentication, form-based authentication, and OAuth2.
- How does Spring Boot handle error handling and exception handling?
Spring Boot provides a centralized error handling mechanism that allows developers to handle errors and exceptions in a consistent way across the application. It provides a set of error handling classes and annotations, such as @ControllerAdvice and @ExceptionHandler, that developers can use to define how errors and exceptions should be handled. Spring Boot also provides detailed error messages and stack traces, which can be useful for debugging.
- What is Spring Data, and how does it work with Spring Boot?
Spring Data is a module of the Spring Framework that provides a set of high-level abstractions for working with databases. It offers a consistent API for interacting with various data sources, such as relational databases, NoSQL databases, and in-memory data stores. Spring Boot integrates with Spring Data to provide easy
- What are the different types of Bean scopes in Spring Boot?
In Spring Boot, there are different types of Bean scopes available. These are:
- Singleton: This is the default scope in Spring Boot. A singleton bean is created only once in the container, and the same instance is returned every time the bean is requested.
- Prototype: This scope creates a new instance of the bean every time it is requested.
- Request: This scope creates a new instance of the bean for every HTTP request.
- Session: This scope creates a new instance of the bean for every HTTP session.
- Global Session: This scope creates a new instance of the bean for every global HTTP session.
- What is the difference between Spring Boot and Spring MVC?
Spring Boot is an opinionated framework that is built on top of the Spring Framework, which is a modular framework for building enterprise applications in Java. Spring Boot provides an out-of-the-box configuration for Spring applications and minimizes the effort required to set up and run a Spring application. Spring MVC, on the other hand, is a module within the Spring Framework that is used for building web applications. It provides a model-view-controller architecture for developing web applications and is used for building RESTful web services.
- What is the purpose of the @Autowired annotation?
The @Autowired annotation is used in Spring Boot to inject dependencies automatically into a Spring managed bean. It is used to wire up the dependencies of a bean without the need for explicit configuration in XML or Java. By using this annotation, we can eliminate the need for manually configuring dependencies and focus on writing the business logic of our application.
- What is the difference between the @Component, @Service, and @Repository annotations in Spring Boot?
The @Component, @Service, and @Repository annotations are used to denote different types of beans in a Spring Boot application. The main differences between them are as follows:
- @Component: This is a generic annotation that is used to denote any Spring-managed component. It is used as a base annotation for all other annotations.
- @Service: This annotation is used to denote a business service in a Spring Boot application. It is used to encapsulate the business logic of an application.
- @Repository: This annotation is used to denote a data access object in a Spring Boot application. It is used to provide data access services to the application.
- What is the use of profiles in Spring Boot?
In Spring Boot, profiles are used to define different configurations for different environments. With profiles, we can define different configurations for development, testing, and production environments. By using profiles, we can ensure that our application works correctly in different environments and that we can easily switch between configurations.
- How can you externalize the configuration properties in Spring Boot?
In Spring Boot, we can externalize the configuration properties by using the application.properties or application.yml file. These files are located in the src/main/resources directory of the Spring Boot application. By using these files, we can configure various properties such as database settings, server settings, and other application-specific properties. We can also use the @Value annotation to inject configuration properties into a Spring bean.
- What are the different types of databases that are supported by Spring Boot?
Spring Boot supports a wide range of databases. Some of the databases that are supported by Spring Boot include:
- MySQL
- PostgreSQL
- Oracle
- MongoDB
- SQL Server
- H2 Database
- Apache Derby
- Cassandra
- Neo4j
These databases are supported through various Spring Boot modules and can be easily configured in a Spring Boot application.
When preparing for Spring Boot interview questions, as an experienced developer, it’s crucial to have a deep understanding of the Spring Boot framework and its related technologies. You should be able to explain Spring Boot Auto Configuration, Spring Boot Actuator, Spring Data JPA, and Spring Security, as well as how these concepts integrate with other Spring modules.
The interviewer may also ask about your experience in designing and implementing RESTful web services, working with databases, testing, and debugging Spring Boot applications. In addition, they may inquire about your knowledge of microservices architecture, Docker, and cloud-based deployment.
To impress the interviewer, you should be able to demonstrate your expertise in all of these areas and show that you have the skills necessary to design, implement, and test robust and scalable Spring Boot applications. Overall, thorough preparation and a strong understanding of Spring Boot and its related technologies are key to succeeding in a Spring Boot Interview.