If you’re interviewing for a job that requires you to know Spring Boot — like a Java Developer, Software Engineer, or Back-end Developer — your technical interview will include questions about this popular Java-based framework.
One of the best ways to prepare for your technical interview is to review Spring Boot interview questions and practice answering them in a mock interview. You can do this with another person or practice on your own. If you want to practice solo, consider filming yourself so you can play back the recording and find any areas you want to improve before your interview.
To help you practice, here are 13 Spring Boot interview questions and tips on how to answer them.
1. What is Spring Boot?
Before jumping into more technical questions, the interviewer may ask you some ice-breaker questions to ease you into the interview. So while this question seems easy, it’s a nice way to kick off your interview before you face the more challenging questions.
If asked, explain that Spring Boot is an open-source, Java-based Spring framework that’s commonly used to create standalone applications that don’t rely on an external web server. Bonus points if you mention that it’s a popular choice for rapid application development (RAD) and building microservices.
2. What are some advantages of using Spring Boot?
There are several advantages to using Spring Boot, and you may want to discuss the ones that you have the most experience with. Not only can you talk in more detail about the advantages if you’ve benefited from them personally, but you’ll likely be able to answer follow-up questions as well. Here are a few advantages you can consider covering in your answer:
- Spring Boot applications “just run.” They don’t require an external web server to function.
- Spring Boot’s opinionated design makes it easy to get started “out of the box.”
- There’s no need for XML configuration with Spring Boot applications.
- Spring Boot helps reduce the amount of source code.
- There’s a large Spring Boot community and a variety of training materials to help developers quickly learn Spring Boot.
3. What are the key features of Spring Boot?
The key features of the Spring Boot framework are:
- Starters: Dependency descriptors
- Auto-configuration: Configures Spring apps based on jar dependencies
- Actuators: Displays an apps operational info
- Security: Provides authentication and authorization features
- Logging: Tracks the events that occur after code is run
4. What are some differences between Spring Boot and Spring?
Spring is a Java-based framework that provides infrastructure support for developing customized Java applications. Spring comes with out-of-the-box modules and also supports many libraries and tools.
Spring is an unopinionated framework, meaning that it’s easy for developers to set up their configurations, architecture, conventions, and best practices. But this means that developers need to spend more time setting up the framework before it’s ready to use.
Spring Boot is essentially an opinionated extension or module of Spring, and it’s often used to create REST APIs. Spring Boot makes default assumptions about software architecture, conventions, and best practices. This makes it faster and more efficient to develop applications in Spring Boot than Spring, provided that the application doesn’t require a lot of customized configuration.
5. How can you create a Spring Boot application with Maven?
Here are a few approaches to creating a Spring Boot application using Maven:
- Spring Maven Project
- Spring Initializr
- Spring Boot CLI
- Spring Starter Project Wizard
6. What’s Spring Boot dependency management?
The Spring Boot framework includes dependency management, which automatically detects, downloads, and stores other frameworks, libraries, and applications you need to run your Spring Boot application. Spring Boot also checks that you’re using the most updated versions of application dependencies and downloads updates as needed.
7. What’s a Spring Boot starter, and what are some available starters?
Spring Boot starters are a set of dependency management providers that enable dependencies in your application. This helps make developing a Spring Boot application both easier and faster.
All available Spring Boot starters are under the org.springframework.boot group. Here are a few of the most popular Spring Boot starters and their features:
- spring-boot-starter: The primary starter, which includes auto-configuration, YAML, and logging
- spring-boot-starter-JDBC: For accessing relational databases with Java database connectivity (JDBC)
- spring-boot-starter-web: For web applications, including with the Spring Model-View-Control (Spring MVC) framework
- spring-boot-starter-data-JPA: For using Spring Data with Java Persistence API (Spring Data JPA) with Hibernate
- spring-boot-starter-security: For use with the Spring Security framework
- spring-boot-starter-AOP: For use with aspect-oriented programming (AspectJ and Spring AOP)
- spring-boot-starter-test: For testing Spring Boot applications
8. What is Thymeleaf, and how do you use it?
Thymeleaf is a Java-based library that contains templates for web applications. It utilizes the concept of natural templates or template files that can be read by browsers directly and displayed properly as web pages. Thymeleaf integrates well with the Spring framework and HTML5 Java web applications.
To use Thymeleaf, you must add it to your Project Object Model (pom.xml) file in Maven.
9. How do you create a Spring Boot project with Spring Initializr?
Spring Initializr is a web application that lets you create an initial Spring Boot project structure before providing a Maven file that you can use to build your application.
To create a Spring Boot project with Initializr,
- Choose the appropriate Maven project and required dependencies, along with other details.
- Generate the project. (This creates a .zip file.)
- Download and extract the project to your system.
- Import the project in Spring.
Since the project type is Maven, the source project should contain the pom.xml file.
10. How can you deploy to a different server with Spring Boot?
To deploy to a different server using Spring Boot, you
— a special type of Java Archive (JAR) file used for packaging web applications. Then, you deploy the WAR file to the new server and run it.
To generate WAR files in Spring Boot, it’s necessary first to add the spring-boot-maven-plugin to the pom.xml file.
11. How can you use Spring Boot for command-line applications?
As with any other Java-based program, you can use Spring Boot to develop command-line applications. However, the application must have a main method, which bootstraps the application by invoking the SpringApplication.run method. The SpringApplication class then starts the Spring container.
After calling this method, you can execute other statements as usual.
12. What does it mean to say that Spring Boot supports relaxed binding?
A property key doesn’t have to be an exact match of a property name with relaxed binding. With frameworks like Spring Boot, environment properties can be written in snake_case, camelCase, kebab-case, or in all uppercase, separated by an underscore.
For example, if a certain property of a class is named myProperty, it can be bound in Spring Boot to any of these environment properties:
13. What is Spring Data?
Spring Data is a Java specification for managing data between Java objects in your application and a relational database. In particular, Spring Data allows you to persist — or store — data and properties about an object so that you can access it later. It also allows data access from non-relational databases (like MongoDB), map-reduce frameworks, and cloud-based data services.
Looking for more Spring Boot interview prep?
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