Updated June 20, 2023
Introduction to Spring Boot Interview Questions
The following article provides an outline for Spring Boot Interview Questions. Spring Boot is a general framework built on top of the Spring framework. It comes up with a new development approach to ease bootstrapping and development of Spring applications. In a typical Spring framework, there are lots of bean and meta configurations in multiple ways, like XML, annotations, and Java configuration. Spring boot avoids all arrangements so that the developer can quickly start a new Spring project within a short period. Spring Boot is not a new approach to solving some problems, but it solves the same problem as the Spring framework but with minimal to no configuration. It follows a default configuration approach which is opinionated. It helps reduce many boilerplate codes and designs to improve development, unit testing, and integration test process.
Now, if you are looking for a job related to Spring Boot, you need to prepare for the 2023 Spring Boot Interview Questions. Every interview is different as per the various job profiles, but still, to clear the interview, you need to have a good and precise knowledge of Spring Boot. Here, we have prepared the critical Spring Boot Interview Questions and answers to help you succeed in your interview.
Below is the list of top Spring Boot Interview Questions that are asked in an interview; these questions are divided into two parts as follows:
Part 1 – Spring Boot Interview Questions (Basic)
This first part covers the basic Spring Boot Interview Questions and Answers.
Q1. What are the advantages of using Spring Boot over the spring framework?
Answer:
Some advantage points are listed below:
- Spring boot provides an opinionated configuration, thus avoiding lots of boilerplate code and design.
- Its applications can be easily integrated into the Spring ecosystem, like Spring Security, Spring AOP, Spring transaction, cache, etc.
- It provides embedded HTTP servers like Tomcat etc., to enhance the development process.
- Spring boot offers a command-line interface, i.e., a CLI tool to develop and test the application, which is prompt and less intrusive.
- Spring boot reduces development time by decreasing the configuration to a minimal or “no-configuration” approach, thus enhancing productivity.
Q2. What is @SpringBootApplication annotation?
Answer:
Before Spring BOOT 1.2, it was very common to use annotations like @Configuration, @EnableAutoConfiguration, and @ComponentScan. The @SpringBootApplication annotation equals all three annotations mentioned before with their default attributes. This means a single annotation is enough now for multiple features like enabling auto-configuration and performing a component scan of beans.
@SpringBootApplication
public class MyApp {
……….
}Q3. Explain the Spring boot starter POM file.
Answer:
The starter POM file actually contains a lot of dependencies, so that project can be up and running quickly within a brief period. It is a combination of dependency descriptors that anyone can include in their application, and automatically all project-related dependencies would be available. Starter POM files also manage the transitive dependencies of the project.
The POM file structure is arriving from a Maven-based application. In other words, a developer creating a project that uses Spring REST for creating rest APIs must include a relevant starter POM file, which will import all required dependencies for the Spring rest application. All the tedious task of searching and configuring dependencies required for a framework is no longer needed.
Q4. Explain the Actuator in Spring Boot.
Answer:
The actuator brings production-ready features to the table for the Spring boot application. Production-ready features like application monitoring, gathering metrics, understanding traffic, and the database state become very crucial to keep the application in a healthy form. A significant benefit of utilizing an Actuator like a library is that a developer can have access to production-grade tools without having to implement any one of these tools. To enable Spring Boot Actuator dependency on our package manager, add the below to your POM file.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>Once this dependency is in the classpath, multiple endpoints are available with the developer.
Q5. What is the way to reload changes on Spring boot without server restart?
Answer:
Any changes are reloaded in spring boot without starting the server by using dev tools.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<optional>true</optional>
</dependency>Spring Boot provides a module called DevTools, which can enhance the productivity of a spring boot developer. It can auto-deploy the changes to the server, with auto-restarting the server. These is the common Spring Boot Interview Questions asked in an interview. Thus, a developer can reload his changes on Spring boot without restarting the server. This package is provided in development mode only, but not in production mode.
Part 2 – Spring Boot Interview Questions (Advanced)
Let us now have a look at the advanced Spring Boot Interview Questions.
Q6. What is the way to run the Spring boot application on a custom port?
Answer:
There is a file called application.properties in Spring Boot. This file can be customized to bring in any change, to alter the behavior of a running spring boot application. If a developer wants to run a spring boot application on a custom port, he can specify the port in an application.properties file:
server.port = 8080
This entry will ensure that the application runs on the 8080 port.
Q7. What is the way to implement the Spring batch in Spring Boot?
Answer:
Batch processing involves large volumes of data records processing. Spring boot batch provides a function that can be reused and is essential for doing batch processing. It also provides services and features that help optimize and partition techniques, resulting in high-volume and high-performance batch jobs.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-batch</artifactId>
<optional>true</optional>
</dependency>The above changes to the POM file will include the necessary packages required for batch processing in a Spring Boot project.
Q8. What is the way to configure logging in the Spring boot application?
Answer:
The developer can easily specify the logging level in an application.properties file:
Logging.level.spring.framework = DebugThis single line in the application properties file will let the spring framework logs to the debug level. If a developer wants to put logs to the file; he can specify the logger.file in application properties.
Logging.file = ${java.io.tempdirectory}/sample.logApart from the above two approaches, a developer can also create a logback.xml file under main/java/resources and specify the logging configuration in the file. Spring boot will automatically pick this file.
Q9. What is the benefit of including the spring-boot-maven plugin?
Answer:
The spring-boot-maven plugin enables the developer to package the code as a jar file and provides a list of commands that are helpful for running the application.
- Spring-boot: run; it will run a spring boot application.
- Spring-boot: repackage; it will repackage jar or war file.
- Spring-boot: build, generate build information.
- Spring-boot: start, and stop, to manage the lifecycle of the spring boot application.
Q10. What is the way to add custom JS code in the Spring boot application?
Answer:
A developer can create a folder by the name of “static”, under the resources folder. Then all the static content can be put into this folder.
Any JavaScript file i.e. test.js would reside in /resources/static/js/test.js
The developer can then refer to this file in JSP like:
<script src = "https://cdn.educba.com/js/test.js"></script>Recommended Articles
We hope that this EDUCBA information on “Spring Boot Interview Questions” was beneficial to you. You can view EDUCBA’s recommended articles for more information.
