65 Spring Boot Interview Questions and Answers (2025)

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

With an auto-configuration feature and support for Spring Initializer, Groovy, and Java, Spring Boot reduces integration, development, and unit test time. It aids the development of fast, responsive, and secure web applications and provides users with a complete configuration and programming model for Java enterprise applications.

Spring Boot utilizes the core features of the Spring application framework and 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?

Mostly used for developing microservices-based applications, Spring Boot offers the following key features for configuring, developing, and deploying a 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 run war files without deploying them
• Includes an Auto-Configuration functionality, allowing users to configure Spring applications automatically
• Supports HTTP client Feign

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

The Spring Cloud that comes with Spring Boot includes vast libraries, which is one of the primary 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 usability. 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?

Below are important Spring Boot dependencies that must be added to a Gradle- or Maven-based application to ensure 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

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6. What are the advantages of Spring Boot?

The advantages of Spring Boot are as follows:

• It is straightforward 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 a 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 quickly build and test our web applications.

7. What are the features of Spring Boot?

Listed below are the main features of Spring Boot:

• It is an excellent Spring module for developing online applications.
• The Spring Application class offers an easy way to bootstrap a Spring Application that can be started from the primary 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?

Step 1: Go to Spring Initializr

• Open Spring Initializr

Step 2: Select Project Settings

• Project: Maven Project
• Language: Java
• Spring Boot: Choose the latest version
• Group: com.example
• Artifact: test
• Name: TestApplication
• Description: About the project
• Package Name: com.example.test
• Packaging: Jar
• Java: 11th version

Step 3: Select Dependencies

• Click “Add Dependencies” and select from the following:
• Spring Web
• Spring Boot DevTools (for development)
• Spring Data JPA (if needed)
• H2 Database (for an embedded database, if needed)
• Thymeleaf (if you are using server-side templating)

Step 4: Download the Project

• Click on Generate (it will download a zip file)

Step 5: Extract the Project

• Extract the downloaded zip file and open it in an IDE of your choice

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

Here are the step-by-step instructions for making a Spring Boot project.

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

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 to 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 the 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: Spring Boot provides command-line completion routines for the BASH and zsh shells.

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

Here’s how you can manually create a Spring Boot application:

Step 1. Create the Project Structure

/demo
/src
/main
/java
/com
/example
/demo
DemoApplication.java
/resources
application.properties
pom.xml

Step 2. Create the pom.xml file

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo</name>
<description>Demo project for Spring Boot</description>
<packaging>jar</packaging>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.7.3</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>

Step 3: Create the Main Application Class

package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}

Step 4: Run the Application

Open your command prompt, navigate to the project folder, and use the following Maven command to run the Spring Boot application:

mvn spring-boot:run

Step 5: Test the Application

Once the application is running, open a web browser or use a tool like Postman to visit the following URL:

http://localhost:8080/hello

Now, you can see the response Hello, World!

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.datasource.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 standard features or technologies. You can quickly get up and running with minimal configuration by including a starter.

15. What is a 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.

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; developers can use it to create HTML templates.

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 do I connect the Spring Boot application to a database using JDBC?

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

20. What is the @RestController annotation in Spring Boot?

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

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Spring Boot Interview Questions for Experienced Developers

The Spring Boot interview questions for experienced developers explain the concepts in depth and are meant to test the candidates' working knowledge.

21. What is the @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 the 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 "Generate" to create the project structure and download the necessary dependencies.
• Start coding your application logic.

23. What is the difference between 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.

Also Read: Spring vs Spring Boot vs Spring MVC

24. What annotations are used to create an Interceptor?

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 to intercept 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 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.

Swagger enables hassle-free application discovery, development, and integration by allowing API consumers to interact with remote services with minimal 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 specific 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 Java data types to SQL (Structured Query Language) data types and Java classes to database tables, relieving developers from scripting data persistence SQL programs.

On the other hand, a Spring Data subproject, 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.

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 autodetected via 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 the specified request handler methods. Once the handler method generates the response body, the @RestController modifies it to an XML or JSON response.

29. What is an annotation in Spring Boot?

Spring Boot Annotations act as metadata to specify data or supplemental information about a program. They do not directly impact the code’s operation or the compiled program's response.

Instead, the annotations simplify configuration and allow task automation, such as error handling, dependency injection, etc. There are multiple types of annotations, such as core annotations, Spring MVC, REST annotations, and others.

30. What is the difference between @component and @bean?

Spring uses the @component and @bean annotations. While @component is used for auto-detection and bean configuration, the @bean annotation is used explicitly for bean declaration.

@component can declare any Spring-managed bean irrespective of its type and scope. @bean is a method-level annotation for explicit bean declaration in the Java configuration class.

Spring Boot Microservices Interview Questions

Some of the critical Spring Boot microservices interview questions to ace the interview are:

31. What do you understand by dumb pipe in Microservices? 

Dumb pipe in Microservices is the messaging or communication mechanism for data exchange between microservices. It is called dumb because it does not participate in decision-making or handle advanced tasks.

Dumb pipe does not require intelligence or a centralized data bus. It handles failure, retires the client, and allows background microservices to connect with other services through an asynchronous communication model.

32.  What are reactive extensions?

Reactive extensions refer to libraries offering tools for implementing reactive programming principles. They simplify the creation of stateful programs that react to events or changes over time and use observable sequences to develop asynchronous and event-based programs.

33. What do you understand by ‘bounded context’? 

Bounded context is the logical boundary that indicates the scope of the domain model within a larger system. It reduces complexity, enhances flexibility, and establishes clear ownership.

Bounded context is among the core patterns in Domain-Driven Design (DDD), which concerns decomposing a complex system into smaller parts. Each of the generated pieces has its own domain model and rules.

34. What is the purpose of the API gateway in Spring Boot microservices?

The API gateway is a single entry point for all API requests and directs them to the appropriate backend services. It also performs other tasks, such as rate limiting, authentication, and caching. Thus, it contributes to simplified communication, improved security and efficiency enhancement.

35. How do you manage distributed transactions between the microservices? 

The Saga pattern can manage distributed transactions. Alternatively, the combination of event sourcing and compensating transactions is also helpful. Tools that help include Zipkin and Cloud Sleuth for distributed monitoring and tracking.

36. What are the challenges in migrating monolithic applications to the microservices architecture?

Some challenges in fragmenting monoliths into smaller services are data consistency management, handling inter-service communication, scalability and fault tolerance. Mitigation solutions involve code refactoring and thoughtful planning of service boundaries and communication patterns.

37. What is the role of service mesh in a microservices architecture?

Service mesh is the software layer concerned with service communication in a microservices architecture. It improves observability by offering real-time visibility into service performance. Thus, it helps recognize issues, optimize performance, and allows data-driven decision-making. 

38. What are some common distributed logging frameworks?

The ELK stack is the most famous distributed logging framework. In this combined framework, ElasticSearch offers a search engine, Logstash contributes to log gathering, and Kibana provides a user interface.

39. What do you need to know when designing microservices? 

The important considerations while designing microservices are scalability, communication between the services, and security. Data management, service discovery, deployment and DevOps are also essential factors to consider. Some design patterns used in microservices include API gateway, Saga pattern, aggregator, circuit breaker, and others.

40. What is the role of containers in the microservice system?

Containers are used in microservices for deployment and orchestration. They offer a lightweight and consistent environment for running applications across various environments. Commonly used containerization technology includes Docker with Kubernetes for container orchestration.

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41. Explain the implementation of circuit breakers.

The circuit breaker pattern contributes to handling failure in distributed systems. It works by breaking or stopping the connection to the failing service or component. Implementing a circuit breaker involves adding necessary dependencies and configuring application properties. Then, the controller is defined, monitoring metrics are set, and the circuit breaker is tested.

42. What do you understand by Spring Cloud Open Feign? 

Spring Cloud OpenFeign is a declarative HTTP client that makes writing web service clients easy. It facilitates communication between microservices and integrates with Spring Cloud. OpenFeign offers flexibility in defining and invoking RESTful web services between the microservices.

43. State the measures for security in Spring Boot microservices architecture.

The security in Spring Boot microservices architecture is possible by incorporating features like authorization and authentication using Spring Security.

Additional techniques that can contribute to the same include OAuth2 for token-based authentication, mutual TLS (mTLS), and role-based access control. Rate limiting and throttling also offer security by preventing Denial of Service (DoS) and Distributed Denial of Service (DDoS) attacks.

44. What is Spring WebFlux?

Spring WebFlux refers to the reactive programming framework in Spring. It allows asynchronous and non-blocking web application development. Spring WebFlux supports both client-side and server-side reactive programming. Its key usage in microservices is seen during the requirement to handle multiple concurrent requests with low latency and minimal resource consumption.

45. What is Coupling?

Coupling refers to the degree or strength of dependency between microservices. There can be loose or tight coupling.

Loose couplings are independent and interact through well-defined APIs, while tight coupling involves high dependency on each other.

Tight coupling is challenging to scale and modify without impacting other services. The presence of high cohesion and low coupling marks a good design.

46. What do you know about different types of tests for microservices? 

There are three types of tests in microservices. The first test assesses the unit and performance at the bottom level. The mid-level includes experimental tests such as stress and usability tests. The top-level tests are concerned with acceptance. All of these are automated tests.

47. What are a few strategies to ensure zero downtime deployments?

Some key strategies here are blue-green deployments, canary releases and rolling updates. Blue-green deployment involves deploying one version (blue) while another (green) is updated.

A canary release encompasses the release of a new version of an application for a limited number of users before it is available to the entire user base. The rolling update includes updates in small increments to allow service availability during the update.

48. What do you understand by the shutdown of the actuator? 

Shutdown in Spring Boot enables graceful application shutdown by ensuring completion of all ongoing tasks before the service stops. Spring Boot Actuator exposes this endpoint (/actuator/shutdown) on the condition that it should be explicitly enabled in the application’s configuration for security reasons.

49. What is CQRS?

Command Query Responsibility Segregation, or CQRS, is the architecture pattern that separates query and command operations. The query is ‘read’, and the command is ‘write’.

The separation is done into distinct models for enhanced performance, security, and scalability. Frameworks such as Spring Data and Event Sourcing make the implementation of CQRS in Spring Boot possible.

50. What are the important metrics for insights into microservices performance?

The key metrics to remain updated include error rates for the frequency of failure requests, latency for request processing time, availability for the period of operation, and throughput for the possible frequency of handling requests in specific time frames.

Most Popular Interview Questions on Spring Boot in 2025

51. What is Dependency Injection in Spring Boot?

Dependency injection in Spring Boot refers to defining dependencies, specifically through constructor arguments.

Additionally, once the construction is completed via the factory method, the properties on the object instance can be set with the dependencies here.

Dependency injection improves testability, promotes loose coupling, simplifies configuration, and eases reusability.

52. What is the purpose of @SpringBootApplication?

The @SpringBootApplication combines 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().

53. 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, injection, custom spring validator, environment abstraction, and validation.

54. What is Spring Boot DevTools?

Spring Boot DevTools are tools that ease application development and optimization. They reduce development time and enhance productivity. They can auto-recompile the code without requiring a manual restart of the application.

DevTools are also used for static resource caching, actuator endpoints, and automatic application restart. The ‘dev tools’ module dependency can easily be added to the project.

55. 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 also add their actuator endpoints.

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.

56. How do you handle exceptions in Spring Boot?

Exception handling in Spring Boot resolves errors and exceptions in APIs. 

In Spring Boot, there are three key ways to handle exceptions: default, @ExceptionHandler and @ControllerAdvice. The latter handles global exceptions.

The default method includes the getCustomer() method, which is defined in CustomerController.

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

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

58. What is Spring Boot Starter?

Spring Boot Starter is a collection of dependency descriptors used to simplify the development process of Spring applications. It is the foundation for web applications, microservices and other Spring-based projects.

It enhances the user’s productivity by allowing them to focus on writing rather than handling infrastructure. Spring Boot Starter also eases POM management and eliminates the need to remember dependency names and versions.

59. 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.

60. 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.

61. 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 

62. 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 help easily manage different environments, optional dependencies, and feature toggles. They can be directly used as a type-level annotation or indirectly annotated with @Component.

63. 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: By default, Spring Security enables protection against Cross-Site Request Forgery (CSRF) attacks.
• 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: This will be done using the @EncryptablePropertySource function.

64. 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.

65. 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 on 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.

Spring Boot Annotations to Prepare for Interviews

To prepare for the Spring Boot interview questions, familiarity with the following Spring Boot annotations is essential:

• Core Annotations

• @SpringBootApplication: It is the main class of the Spring Boot application. It combines three annotations, i.e., @ComponentScan, @Configuration and @EnableAutoConfiguration.
• @ComponentScan: It specifies packages for Spring components, such as services, controllers, and repositories.
• @Configuration: It marks the class comprising configuration logic and bean definitions as a configuration class.
• @EnableAutoConfiguration: It depends on the classpath and properties in the application.yml or application.properties file.

• Dependency Injection Annotations

• @Autowired: It injects dependencies into constructors, setter methods, or fields of a class.

• Data Handling Annotations 

• @RequestBody: This annotation requests the body from an HTTP request and binds it to a method parameter.
• @ResponseBody: This annotation directs the return value to the HTTP response body.

• Controller Annotations 

• @RestController: It marks a class that handles incoming HTTP requests and provides output in JSON, XML and others.
• @Controller: If a class provides output response as views, this annotation marks it as a controller.

• Exception Handling Annotations

• @RestControllerAdvice: It is the global exception handler dealing with all the application errors.
• @Exceptionhanndler: It handles specific exceptions and customizes the responses on their occurrence.

• Path Variable and Request Parameter Annotation 

• @RequestParam: It extracts query parameters from the URL and binds them to method parameters. This annotation provides key-value pairs from the URL’s query string for processing.
• @PathVariable: It extracts values from the URI path and binds them to method parameters. This annotation provides dynamic parts of the URL.

• Service and Repository Annotations 

• @Service: This annotation marks a class as a service if it comprises business logic.
• @Repository: It marks the class as a repository if it handles data access.

• Request Mapping Annotations

• @RequestMapping: It maps the method in a controller to specific HTTP endpoints.
• @GetMapping and @PostMapping: It is the specialized versions of @RequestMapping for specific HTTP methods.

• Other Annotations

• @Qualifier will specify the beans to inject in the presence of numerous beans of the same type.
• @Async and @enableAsync will mark the method for asynchronous running and enable asynchronous support.
• @Profile to define different sets of beans for activity in defined environments.
• @Value will inject values from external sources into Spring beans.
• @Postconstruct and @PreDestroy to mark methods for execution after the generation of the bean.

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Conclusion

Mastering Spring Boot is a significant step toward becoming a proficient Java developer. The Spring Boot interview 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 skills.

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.

If you want to broaden your expertise and become a versatile developer, consider enrolling in the Full Stack Java Developer Master’s Program. This comprehensive program covers everything from front-end technologies to robust server-side applications like Spring Boot, preparing you for a successful career in full-stack development.

By becoming a certified full-stack Java developer, you can enhance your skills, build dynamic applications, and open the door to numerous opportunities in the tech world.

FAQs

1. How do you explain the Spring Boot project in an interview?

Begin by providing an overview of the project, highlighting its use of the Spring Boot framework and its features. Then, discuss the project's purpose and functionality, including key features and technologies. 

2. Is Spring Boot in demand in 2025?

The simplified development, support for microservices, flexibility, and simplicity make it a widely used framework. Hence, it is currently in demand and will remain so.

3. What is POM in Spring Boot?

Project Object Model, or POM in Spring Boot, is an XML file that comprises information on the project and its building method. It contains details on the project version, description, developers, mailing lists, plugins, build settings, and profiles. POM offers dependency and build lifecycle management.

4. What is the REST API in Spring Boot?

It is an application programming interface (API) that exposes HTTP methods for performing CRUD operations (Create, Read, Update, and Delete) on resources. Here, the REST stands for the REpresentational State Transfer.

5. What is Spring Boot used for?

Spring Boot simplifies the development of Java-based applications. Here’s what Spring Boot is used for:

• Build standalone applications
• Microservices development
• Spring configuration
• Faster development cycle
• Create REST APIs
• Database integration