Top Spring Boot Interview Questions [2022]

Spring Boot is constantly coming up with new ways to make application development easier. Spring Boot and microservices are highly regarded technologies/frameworks in the tech industry, and they are among the most widely used technologies with Java to develop web applications. It aims to build a standalone Java system from the ground up that is very robust and maintainable due to its fast, low configuration, built-in server, and monitoring features.

You’ve probably considered enrolling and beginning to learn the ins and outs of those frameworks and attempting to complete the spring boot questionnaire that is asked during the interviews.

Contents
  1. Top Spring Boot Interview Questions
  2. Conclusion

Top Spring Boot Interview Questions

Q1. Describe the term “Spring Boot.”

Sprint Boot seems to be a spring framework based on Java used for Rapid Application Development (to build standalone microservices). It also includes auto-configuration and embedded application server support, such as Tomcat, Jetty, etc.

Q2. What are the features of spring boot?

Spring Boot features that set it apart:

  • This leads to self spring application with a simple user interface.
  • It has Tomcat and jetty embedded, so all you have to do is code and run the application.
  • Provide features ready for production, such as performance measures, medical checks, and externalized configuration.
  • There is no requirement for XML configuration.

Q3. What are the advantages of utilizing Spring boot? What distinguishes it from the Spring framework?

Spring Boot has a large community behind it, and Spring Cloud has a plethora of modules that allow it to implement almost every prevalent open-source tool. Spring Boot makes it very simple to create microservices, and spring Boot is one of the top frameworks for building microservices quickly if you are transitioning to microservices architecture. Spring Boot makes it very simple to create a standalone application by providing auto configurations, and it includes performance-ready features such as Actuator.

It is commonly used for:

• Website creation (server-side).

• Software creation.

• arithmetic

• Scripting for the system.

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Q4. What are the main components of Spring Boot?

The four main components of a spring boot are as follows:

  • Auto-configuration of Spring Boot.
  • CLI for Spring Boot.
  • POMs for Spring Boots.
  • Actuators for Spring Boots

Q5. Mention the benefits of Spring Boots.

  • It creates standalone applications with several features common to many different types of projects.
  • It provides auto-configuration to pile a set of pre-defined configurations for a quick application start.
  • It includes embedded Tomcat, servlet containers, and Jetty to avoid using WAR files.
  • Spring Boot offers a judgemental point of view to reduce developer time and energy and simplify maven configurations.
  • Provides a command-line interface (CLI) tool for developing and testing applications.
  • Seamlessly integrates with Spring Ecosystem components such as Spring JDBC, Spring ORM, Spring Data, and Spring Security by seeking to avoid boilerplate code.
  • It includes Spring Boot starters to make sure dependency governance and offers a variety of security metrics.

Q6. In Eclipse, how do I generate a Spring Boot project?

You can just go to the spring official website and enter details such as version, Maven or Gradle project, groupId, artifactId, requisite interconnections, and then click CREATE PROJECT. Spring Initializer is one method for creating a spring boot project in eclipse. After you’ve created the project, you could even download it, retrieve it, and transfer it into Eclipse or STS.

Q7. What are your thoughts on Spring Boot starters?

It thus is among the most commonly encountered Java Spring Boot interview questions in technical interviews. Spring Boot starters are a collection of components that serve as interconnections during the development phase. Starters aid at the beginning of the application development process by providing various dependencies. The org. springframework.boot group contains Spring Boot starters.

Q8. Describe how to use Maven to create a Spring Boot application?

There are several methodologies for establishing a Spring Boot implementation using Maven, but if you had to pick a few, these are the methods to create a Spring Boot project/application using maven:

  • CLI for Spring Boot
  • Spring Project Starter Wizard
  • Spring Maven Project Initiation

Q9. What exactly does the @SpringBootApplication addendum do?

The @SpringBootApplication annotation is roughly comparable to using default attributes of @Configuration, @EnableAutoConfiguration, and @ComponentScan. Spring Boot allows developers to use a single annotation rather than multiple annotations. However, as we all know, Spring provides flexible features that we can use for each annotation based on the needs of our project.

Q10. What’s the contrast between Spring and Spring Boot?

The difference between the both is explained as-

Spring:

  • It is a framework for dependency injection.
  • Its primary purpose is to maintain the lifetime of Java classes (beans). There is a lot of boilerplate configuration in it.
  • Configuration is done using XML.
  • This needs the patience to get a spring application up and running, primarily to boilerplate code.

Spring Boot:

  • It is a collection of pre-configured paradigms and techniques that aid in eliminating boilerplate configuration.
  • Annotations are used.
  • It’s used to generate production-ready code.

Q11. Mention the potential external configuration sources.

Spring Boot enables developers to operate the same application in multiple environments. This is accomplished through the support it provides for external configuration. It specifies the necessary configuration properties using environment variables, properties files, command-line arguments, YAML files, and system properties.

As a result, the following are the most likely sources of external configuration:

  • Application Properties – To load the properties, Spring Boot tries to search for the application properties file or its YAML file in the current working directory, classpath root, or config directory.
  • Command-line arguments – Spring Boot accepts command-line arguments and decodes them to properties. Then it keeps adding them to the collection of environment properties.
  • Profile-specific characteristics – Such characteristics are read from the application-profile.properties or YAML file. This file is located in the same directory as the non-specific property files, and the profile placeholder makes reference to an active profile.

Q12. What exactly is an actuator in a spring boot?

These are of the favourite aspects of a spring boot is the Actuator, which includes manufacturing features that will help you control and manage your application. You can supervise what is going on within the operating application with the help of an actuator.

The actuator reliance calculates the performance measures and makes them accessible as a fresh exit point in your application, and retrieves all necessary data from the web. With the Actuator, you can identify beans, the wellness of your application, CPU usage, and many other things.

Q13. What are the various starters accessible in Spring Boot?

In technical interviews, this is a popular Java Spring Boot question. Spring Boot’s various starters include:

  • Spring-boot-starter-aop
  • Spring-boot-starter-test
  • Spring-boot-starter-jdbc
  • Spring-boot-data-jpa
  • Spring-boot-starter-web
  • Spring-boot-starter-security

Q14. What is the purpose of Spring Boot DevTools?

Spring Boot Dev Tools are a sophisticated set of tools that aim to streamline the process of developing an application. If the application is in production, this module is auto disabled, and archive repackaging is also disabled by default. As a result, the Spring Boot Developer Tools apply properties to the appropriate development environments. To include the DevTools, simply include the mentioned dependency in the pom.xml file:

Q15. What exactly is a Spring Initializer?

Spring Initializer is just a web application that assists you in creating a basic spring boot project structure.

Q16. How do you change the port in Spring Boot?

The default port for launching your SpringBoot application is 8080.

Simply add the server.port=8084c(your port number) property to your application to alter the port number.

Initiate your application after saving the properties file.

Q17. What exactly is the RAD model?

The Rapid Application Development (RAD) process is an adaptation of the waterfall model that focuses on creating software in a brief span of time. RAD uses iterative processes.

The SDLC RAD model includes the following phases:

  • Modeling a business
  • Modeling of data
  • Modeling of Processes, Application Generation, Testing, and Turnover

Q18. Explain the various phases of the RAD model.

This is some of the most frequently asked interview questions about the various phases of the RAD mode:

Business Modeling: The product is designed to show the flow of data and dispersion among multiple business channels.

Data Modeling: The information gathered from business modelling is fine-tuned into a series of data objects relevant to the business.

Application Generation: Automated tools are being used to build software by converting process and data models in and out of prototypes.

Q19. How do we enable the spring boot application’s debugging log?

There are three ways to enable debugging logs.

With the debug switch – we can run the application.

In the application.property file, we could even establish the logging.level.root=debug property.

Within the supplied logging configuration file, we could really establish the root logger’s logging level to troubleshoot.

Q20. In Spring Boot Actuator, how do we create a customized endpoint?

In Spring Boot 2.x, you could use @Endpoint annotation to create a custom endpoint. Spring Boot as well reveals endpoints over HTTP using @WebEndpointor and @WebEndpointExtension with the assistance of Spring MVC, Jersey, and other libraries.

Q21. What Are all the Primary Annotations of Spring Boot?

Spring Boot’s primary annotations are found in the org.springframework.boot.autoconfigure and its sub-packages. Here are a few basic examples:

@EnableAutoConfiguration – tells Spring Boot to take a peek at auto-configuration beans on the classpath and implement them automatically.

@SpringBootApplication – the main class of a Boot Application. This annotation manages to combine the annotations @Configuration, @EnableAutoConfiguration, and @ComponentScan with their default attributes.

Q22. How do we make a war file in Spring Boot?

To make a war file in spring boot, describe your packaging file as a war in your pom.xml file (if it is a maven project).

Then simply run Maven clean and install, and your application will begin to build. When the build is complete, simply navigate to your Target folder and look for the.war file that was created for your application.

Q23. How Do We Deploy Spring Boot Web Apps as Jar and War Files?

Typically, a web application is packaged as a WAR file and then deployed to an external server. This enables us to run lots of applications on the same server. It was a wonderful way that can save resources when CPU and memory were scarce. However, times have changed. Now that computer hardware is reasonably priced, the focus has shifted to server configuration. A minor error in server configuration during deployment can have disastrous consequences.

Spring addresses this issue by providing a plugin, spring-boot-maven-plugin, that allows you to package a web application as an executable JAR.

Simply add the following plugin element to pom.xml to include this plugin:

Q24. What Does It Mean When a Spring Boot Allows for Relaxed Binding?

Spring Boot’s relaxed binding is relevant to the type-safe binding of configuration properties. The best approach to a property does not have to be an ideal fit for the property name when using relaxed binding. This type of environment property could be written in camelCase, kebab case, snake case, or uppercase with words separated by underscores.

For example, if a bean class property with the @ConfigurationProperties annotation is named myProp, it can be bound to any of the following environment properties: myProp, my-prop, my prop, or MY PROP.

Q25. What exactly is JPA in spring boot?

JPA stands for Java Persistence API. It is a standard that allows you to do ORM (Object-Relational Mapping) when linking to a relational database. ORM allows you to plot your entity classes in SQL tables, so whenever you link to the database, you don’t have to do any querying; the framework does it for you.

As such, whenever you need to link up your Java application to a relational database, you must be allowed to do something like JDBC and run SQL queries, after which you receive the outcomes and transform them into Object instances.

Q26. Can we use Spring Boot to build a non-web application?

Yes, we could indeed create a non-web application by stripping away the web dependencies from the classpath and altering how Spring Boot produces the application context.

Q27. Could it be probable in Spring Boot to modify the port of the embedded Tomcat server?

Yes, it is conceivable. In the application, use server.port. properties

Q28. What is the meaning of autoconfiguration in spring boot?

AutoConfiguration is how Spring Boot automatically sets up all infrastructure beans. Relying on the dependencies in your application’s classpath, this proclaims the built-in beans/objects of the Spring specific module such as JPA, spring-security, and so on.

Q29. In Spring Boot, could indeed we override or replace the Embedded Tomcat server?

Yes, we can even use the Starter dependency in the pom.xml file to replace the Embedded Tomcat server with any server. For example, if you want to use a jetty server in your project, you could even add spring-boot-starter-jetty as a dependency.

Q30. Is it possible to turn off the default web server in the Spring boot application?

Yes, we could perhaps set up the web application type using the application.properties, e.g. spring.main.web-application-type=none.

Conclusion

We can tell that spring boot will not be replaced as the “go-to framework” in Java over the next few years, but almost all other frameworks have similar characteristics, so that skill sets would be interchangeable. We hope the above set of Spring Boot Interview Questions Responses helps you prepare for your interviews.

Jeetu Sahu is A Web Developer | Computer Engineer | Passionate about Coding, Competitive Programming, and Blogging

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