Top Spring Boot Interview Questions and Answers for 2025

Top Spring Boot Interview Questions and Answers for Freshers

Here are the most frequently asked spring boot interview questions for beginners.

1. What is Spring Boot and what are its Benefits?

Spring Boot represents a fusion of the lightweight Spring application framework, configuration annotations, and embedded HTTP server.

Made available with an auto-configuration feature and support for Spring Initializer, Groovy, and Java, Spring Boot reduces Integration Test, Development, and Unit Test time.

It aids the development of fast, responsive, and secure web applications, providing users with a complete configuration and programming model for Java enterprise applications.

Spring Boot, utilizing the core features of the Spring application framework, offers a faster development technique for RESTful or REST architecture-based web services. 

2. What makes Spring Boot superior to JAX-RS?

By leveraging Spring Boot features, users can experience significant advantages over JAX-RS, including:

• Fast deployment
• High scalability
• Container compatibility
• Minimal configuration
• Lower production time
• Increased productivity 
• Reduced development time
• Easy monitoring and management of applications

3. What Spring Boot features help develop Microservices Applications?

Primarily used for developing microservices-based applications, Spring Boot offers the following key features for configuring, developing, and deploying microservices architecture.

• Integrates a tool called the Actuator, which enables users to manage and monitor applications
• Provides support for embedded servers, such as Jetty and Tomcat
• Users can simply run war files, without deploying it
• Includes an Auto-Configuration functionality, allowing users to configure Spring applications automatically
• Supports HTTP client Feign

4. Why Spring Boot is preferred over any other framework?

The Spring cloud that comes with Spring Boot, includes vast libraries, which is one of the major reasons most developers prefer the Java-based Spring Boot. In addition, Spring Boot offers superior compatibility with Spring frameworks and provides excellent support for docker containerization, heightening performance, and useability. Some of the most compelling reasons for using Spring Boot include: 

• Provides the best means to configure Java beans
• Offers robust batch processing 
• Helps users effectively manage Representational State Transfer (REST) endpoints
• Integrates an auto-configuration tool, eliminating the need for manual configuration 
• Enables  annotation-based configurations
• Ease of dependency management
• Includes embedded servlet containers

5. What are the key dependencies of Spring Boot?

Mentioned below are important Spring Boot dependencies that need to be added to a Gradle-based or Maven-based application, to ensure application compatibility with Spring Boot features.

• spring-boot-starter-parent
• spring-boot-maven-plugin
• spring-boot-starter-test
• spring-boot-starter-security
• spring-boot-starter-actuator
• Spring-boot-starter-web

6. What are the advantages of Spring Boot?

The advantages of Spring Boot are as follows:

• It is very simple to create Spring-based apps in Java or Groovy.
• It cuts down on development time and also increases the output.
• It eliminates the requirement to write repetitive code, annotations, and XML configuration.
• It is straightforward to combine Spring Boot Application with its Spring Ecosystem, which includes Spring JDBC, Spring ORM, Spring Data, and Spring Security, among other things.
• It employs the "Opinionated Defaults Configuration" approach to minimize developer effort.
• It provides Embedded HTTP servers such as Tomcat, Jetty, and others to help us build and test our web applications quickly.

7. What are the features of Spring Boot?

Features of Spring Boot:

• It is an excellent Spring module for developing online applications.
• Spring Application class offers an easy way to bootstrap a Spring application that can be started from the main method.
• Spring Boot utilizes application events and listeners to handle various tasks. It enables us to build factory files to add listeners.
• Spring Boot allows you to activate admin-related features for your application.   

8. How do you create a Spring Boot application using Maven?

Let us learn how to create a Spring Boot application with Maven. Consider that Maven is already installed and configured on your machine. First, create a Spring Boot application with a single main class to simplify it.

9. How do you create a Spring Boot project using Spring Initializer?

Step-by-step instructions for making a spring boot project.

Step 1: Go to https://start.spring.io and launch Spring Initializr.

Step 2: Specify Project Details—Once all the details are entered, select the Generate Project button to generate and download a Spring Boot project. Then, unzip the downloaded zip file and transfer it into your preferred IDE.

Step 3: Next open Eclipse and import the file.

Select File -> Import -> Existing Maven Project in Eclipse. On the next page, navigate to or type in the path to the folder where you extracted the zip file. After you select Finish, Maven will take some time to download all the dependencies and initialize the project.

10. How do you create a Spring Boot project using boot CLI?

Setting up the CLI: The Spring Boot CLI (Command-Line Interface) can be directly installed using SDKMAN!

Employing the CLI: Once the CLI has been installed, you can launch it by typing spring and hitting Enter.

Launch a New Project: You can initiate a new project without leaving the shell by using start.spring.io and the init command.

Using the Embedded Shell: For the BASH and zsh shells, Spring Boot provides command-line completion routines.

11. How do you create a simple Spring Boot application?

Check out the simplest method for creating a basic "Hello World!" example. Of course, there are many ways to accomplish that, but we'll choose the simplest one. We'll use Spring Initializr. With the selected language, version, and dependencies, that tool will automatically build the base project for us. 

12. What are the Spring Boot Annotations?

1. @SpringBootApplication: The annotation indicates a configuration class that defines one or more @Bean methods and initiates auto-configuration and component scanning.
2. @EnableAutoConfiguration: Using the jar dependencies you have provided, the @EnableAutoConfiguration annotation instructs Spring Boot to "guess" how you want to configure Spring.
3. @ConditionalOnMissingClass: The Class conditions are these comments' home. Depending on the existence or absence of particular classes, a configuration can be included using the @ConditionalOnClass and @ConditionalOnMissingClass annotations.
4. @Conditional: A class evaluating the specific condition can be made for even more complicated circumstances.

13. What are the Spring Boot properties?

Spring Boot Properties files are used to configure its auto-configuration and application properties. Spring Boot has many properties that can be used to configure the application's behavior. Some of the commonly used properties in Spring Boot include server.port, spring.profiles.active, spring. data source. URL, spring.jpa.show-sql, and many more.

14. What are the Spring Boot Starters?

Spring Boot Starters are a set of pre-configured dependencies that can be easily included in your project to quickly start using common features or technologies. By including a starter, you can quickly get up and running with minimal configuration.

15. What is Spring Boot Actuator?

Spring Boot Actuator is a set of features that provides monitoring and management capabilities for your Spring Boot application. Actuator endpoints expose information about your application, such as health status, metrics, and environment variables, that can be used to monitor and manage it.

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16. What is thyme leaf?

Thyme Leaf is a popular templating engine used in Spring Boot applications to build dynamic web pages. It is humanly readable, and developers can use it to create templates that can be rendered in HTML.

17. How to use thyme leaf?

​​To use Thymeleaf in a Spring Boot application, you should include the thymeleaf-spring-boot-starter dependency in your project.

18. How do you connect Spring Boot to the database using JPA?

Configure the JPA properties in the application.properties or application.yml file to connect Spring Boot to a database using JPA. 

19. How to connect the Spring Boot application to a database using JDBC?

To connect the Spring Boot to a database using JDBC, configure the JDBC properties in the application.properties or application.yml file.

20. What is @RestController annotation in Spring Boot?

@RestController is a Spring Boot annotation used to create RESTful web services.

21. What is @RequestMapping annotation in Spring Boot?

@RequestMapping is a Spring Boot annotation that maps a URL request to a controller method.

22. How do you create a Spring Boot application using Spring Starter Project Wizard?

Follow the steps mentioned below to create a Spring Boot application using the Spring Starter Project Wizard; you need to follow these steps:

• Open your preferred IDE and select the "New Project" option.
• Next choose the "Spring Initializr" or "Spring Starter Project" option.
• Fill in the required project information, including the name, description, and dependencies.
• Click on "Generate" to create the project structure and download the necessary dependencies.
• Start coding your application logic.

23. Spring Vs Spring Boot?

Spring is a framework that provides various modules for building enterprise-level applications.

Spring Boot is a framework that simplifies Spring development by providing a pre-configured environment that enables developers to focus on building the application logic.

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Top Spring Boot Interview Questions for Experienced Developers

The spring boot interview questions for experienced developers deal with the concepts in greater depth and are meant to test the candidates' working knowledge.

24. What annotations are used to create an Interceptor?

Interceptor is a prominent functionality of Spring Boot. It uses the annotated class @Component and implements the interface HandlerInterceptor.

The interface contains 3 main methods, which are:

The preHandle() Method − preHandle() is used to intercept the request before the handler's implementation. If preHandle() returns a “true” boolean value, developers can continue with handler execution. If preHandle() returns a “false” boolean value, developers should stop the handler execution. 

preHandle() implementation looks like:

 @Override

    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {

        logger.info(" Pre handle ");

        if(httpServletRequest.getMethod().equals("GET"))

            return true;

        else

            return false;

    }

The postHandle() Method − postHandle() is used for intercepting a request following the handler's implementation. It allows the manipulation of the ModelAndView Object before users render it.

postHandle() implementation looks like:

@Override

    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {

        logger.info(" Post handle ");

        if(modelAndView.getModelMap().containsKey("status")){

            String status = (String) modelAndView.getModelMap().get("status");

            if(status.equals("SUCCESS!")){

                status = "Authentication " + status;

                modelAndView.getModelMap().put("status",status);

            }

        }

    }

The afterCompletion() Method − A HandlerInterceptor callback approach, the afterCompletion() method is used when the entire request gets completed.

afterCompletion() looks like:

@Override

    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {

        logger.info(" After Completion ");

    }

}

25. What is a Swagger in Spring Boot?

Swagger is used to detail and document RESTful APIs in a machine-readable and human-readable format that is easily understandable for testers, developers, and individuals with little knowledge of source code.

Enabling hassle-free application discovery, development, and integration, Swagger allows API consumers to interact with remote services with minimum implementation logic.

26. What are Profiles in Spring Boot?

Profiles in the Spring framework enable users to map components and beans to specific profiles, such as the Development (dev) profile, Production (prod) profile, or the Test profile. 

In Spring Boot, the annotation @Profile maps components and beans to a certain profile. 

Developers can also set up profiles using the SpringApplication, for instance, SpringApplication.setAdditionalProfiles("dev");

27. What differentiates Spring Data JPA and Hibernate?

A Java Persistence API (JPA) implementation, Hibernate facilitates Object-Relational Mapping (ORM), allowing users to store, retrieve, map, and update application data to and from Java objects and relational databases. Hibernate maps the data types in Java to SQL (Structured Query Language) data types and the classes in Java to the database tables, relieving developers from scripting data persistence SQL programs. 

On the other hand, a Spring Data sub-project, Spring Data JPA, abstracts the DAL (Data Access Layer) by applying JPA and Object–Relational Mapping implementations, such as Hibernate. Spring Data JPA facilitates the smooth implementation of JPA repositories and intends to improve the overall implementation of DAL greatly.

28. How are the @RestController and @Controller Annotation different?

The traditional Spring @Controller annotation specifies that an annotated class represents a controller. It’s a @Component specialization and autodetected via the classpath scanning. The @Controller annotation and the annotated handler methodologies are used based on @RequestMapping annotations.

Developers use the @RestController annotation to develop RESTful web services, utilizing the Spring Model–View–Controller (MVC). The Spring @RestController maps the request data using specified request handler methods. Once the handler method generates the response body, the @RestController modifies it to an XML or JSON response.

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Most Popular Interview Questions on Spring Boot in 2025

29. What is Dependency Injection in Spring Boot?

Dependency injection in Spring Boot refers to the process of defining dependency, specifically through constructor arguments. Additionally, the dependencies here can also be set by the properties on the object instance once the construction is completed via the factory method. Dependency injection improves testability, promotes loose coupling, simplifies configuration and eases reusability.

30. What is the purpose of @SpringBootApplication?

The @SpringBootApplication is a combination of three annotations: @AutoConfiguration, @ComponentScan and @Configuration. It combines the functions of these three annotations and is internally used to configure the application according to the dependencies added while creating the project. The annotation also bootstraps the application and can be started in the main class by invoking SpringApplication.run().

31. How does Spring Boot handle externalized configuration?

The externalized configuration feature in Spring Boot allows users to use a single application code across different environments. This is achieved by separate configuration storage. Multiple ways can be used to achieve externalized configuration, such as configuration files, structured objects, property sources and injection, custom spring validator, environment abstraction, validation, and others. 

32. What is Spring Boot DevTools?

Spring Boot DevTools are tools that ease application development and optimization. These tools reduce development time and enhance productivity. They can auto-recompile the code without the requirement to restart the application manually. DevTools are also used for static resource caching, actuator endpoints, and automatic application restart. The ‘spring-boot-devtools’ module dependency can easily be added to the project.

33. What is the use of Spring Boot Actuator endpoints?

Sprint Boot comprises multiple built-in Actuator endpoints that monitor and interact with the application. Users can add their actuator endpoints as well. The endpoints can be enabled, disabled and exposed through HTTP or JMX. These are used for the application's health checkup to gather metrics, information and the list of beans. The actuator endpoints are useful for knowing the mappings between URLs and controller methods, accessing environment properties, gaining thread dumps, and offering multiple other information.

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34. How do you handle exceptions in Spring Boot?

Exception handling in Spring Boot resolves errors and exceptions in APIs. There are three key ways to handle exceptions in Spring Boot: default, @ExceptionHandler and @ControllerAdvice. The latter handles global exceptions. The default method includes the getCustomer() method, defined in CustomerController.

35. What is the difference between @Component, @Service, and @Repository annotations?

The @Component annotation is used to declare the general class as a Spring-managed bean class. @Service is used to declare any class as a Business logic (Service) class. Further, the @Repositroy annotation is used to annotate classes that perform database operations, such as Data Access Objects (DAOs).

36. What is Spring Boot Starter?

Spring Boot Starter is a collection of dependency descriptors used to simplify the development process of Spring applications. It serves as the foundation for web applications, microservices and other Spring-based projects. It enhances the user’s productivity by directing the focus on writing rather than working on infrastructure handling. Spring Boot Starter also eases POM management and eliminates the requirement to remember dependency names and versions. 

37. What are the different scopes available in Spring Boot?

Scope provides information about bean instances in the application. They are of different types, such as: 

• Singleton: It is the default scope where only a single instance is used for the complete application context. 
• Prototype: Here, each request creates a new bean instance. 
• Request: Every HTTP request creates a new bean instance.
• Session: Each HTTP session creates a new bean instance. 
• Application: The entire web application gets a new Bean instance

38. How does Spring Boot support logging?

Sprint Boot supports logging to ease logging integration and configuration in the application. The default logging frameworks are Java Util Logging, Logback, and Log4j2. Further, Simple Logging Facade for Java (SLF4J) is used to switch logging frameworks. 

39. What is Spring Boot’s embedded server, and how do you configure it?

The feature of an embedded server in Spring Boot offers direct access to the web server within the application. It removes the need for separate server installation and configuration, easing the deployment process. The different methods to configure the server are: 

• Using application.properties or application.yml
• Via programmatic configurations 
• Through command-line agreements 

40. What is the purpose of Spring Boot’s @Conditional annotations?

The @Conditional annotations create customizable and flexible configurations by applying specific settings or loading beans when certain conditions are met at runtime. These features contribute to easily managing different environments, optional dependencies and feature toggles. They can be directly used as a type-level annotation or indirectly annotated with @Component.

41. How do you secure a Spring Boot application?

The different ways to secure the Spring Boot application include:

• Password encoder: It is the sprint security password management process component that encodes and decodes the password by default. 
• HTTPS: It encrypts the data during the process of transmission. Enable TLS/SSL in application.properties to enable this protection. 
• CSRF protection: Protection against Cross-Site Request Forgery (CSRF) attacks is enabled by default in Spring Security. 
• Method level security: It is used when low privileged or unauthorized user access to sensitive functions is encountered. The @PreAuthorize annotation can be used here. 
• Parameterized queries: It is used to protect against SQL injections. 
• Rigorous input validation: The input's length, type, format and range must be validated. Built-in validation can be used here. 
• Sensitive data encryption: It will be done by the @EncryptablePropertySource function

42. How does Spring Boot achieve auto-configuration?

The Spring Boot auto-configuration is achieved according to the jar dependencies the user adds. Spring Boot scans the classpath for configuration classes and specific libraries and automatically configures the beans based on them. The feature eliminates the manual configuration requirements.

43. What are Spring Boot filters, and how are they used?

The Spring Boot filters are powerful tools that positively influence the request-response lifecycle. They are the components of the servlet API that function at HTTP requests and responses. The filters serve the key aim of logging, authentication and input validation. They are also used for data transformation, caching, and security checks.

Conclusion

Mastering Spring Boot is a significant step toward becoming a proficient Java developer. The questions and answers discussed in this article are designed to provide a solid foundation in Spring Boot, helping you confidently approach interviews and demonstrate your technical prowess. Whether you're aiming for a role in a startup or a position at a large corporation, your knowledge of Spring Boot can set you apart in the competitive tech industry.

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