Spring Boot Interview Questions for Freshers (2026): 30 Questions With Answers You Can Say Out Loud

Let’s be honest. If you’ve put Spring Boot on your resume, you will be asked about it. Every Java full stack interview for a fresher seems to include a few of the same questions: What is Spring Boot? What does @SpringBootApplication do? What’s the difference between @Controller and @RestController? The good news is that these questions repeat, so you can prepare for them.

This guide covers the Spring Boot interview questions for freshers that come up most often, along with Spring Boot interview questions and answers written the way you’d actually say them, Spring Boot REST API interview questions, Spring Data JPA interview questions, and the tricky follow-ups interviewers like to throw in. You’ll also find code, a revision sheet and a short plan so you’re not cramming the night before.

How to Use This Guide

Each question has three parts:

• Say it like this: a short answer you can speak in 20 to 40 seconds.

• Add this if they push: extra depth for a follow-up.

• Avoid: the common wrong answer.

Don’t memorise the words. Read the answer, understand the idea, then explain it in your own sentences. Interviewers can tell the difference within ten seconds.

What Gets Asked Most: An Illustrative View

This is an illustrative guide, not an official survey, and every company is different.

PART 1: THE BASICS (Questions 1 to 8)

1. What is Spring Boot?

Say it like this: Spring Boot is a framework built on top of Spring that makes it quick to create stand-alone, production-ready applications. It removes most of the manual configuration by giving you auto-configuration, starter dependencies and an embedded server, so you can run an app with a simple main method.

Add this if they push: It doesn’t replace Spring. It sits on top of it and removes the repetitive setup.

Avoid: “It’s a new language” or “It’s only for web apps.”

2. What is the difference between Spring and Spring Boot?

Say it like this: Spring is the core framework that provides dependency injection and many modules. Spring Boot is a tool that makes using Spring much easier through auto-configuration, starters and an embedded server, so you write far less XML or manual configuration.

3. What are the main features of Spring Boot?

Say it like this: Auto-configuration, starter dependencies, an embedded server, externalised configuration through properties files, production tools such as Actuator, and no need for XML configuration.

4. What does @SpringBootApplication do?

Say it like this: It’s a convenience annotation that combines three annotations: @Configuration, @EnableAutoConfiguration and @ComponentScan. Together they mark the class as a configuration source, turn on auto-configuration and scan the package for components.

java

@SpringBootApplication
public class StudentApplication {
    public static void main(String[] args) {
        SpringApplication.run(StudentApplication.class, args);
    }
}

@SpringBootApplication
public class StudentApplication {
    public static void main(String[] args) {
        SpringApplication.run(StudentApplication.class, args);
    }
}

@SpringBootApplication
public class StudentApplication {
    public static void main(String[] args) {
        SpringApplication.run(StudentApplication.class, args);
    }
}

Add this if they push: Component scanning starts from the package of this class, so keep it in the root package or your beans won’t be found.

5. What is auto-configuration?

Say it like this: Auto-configuration means Spring Boot looks at the libraries on your classpath and configures beans for you automatically. For example, if spring-boot-starter-web is present, it configures an embedded Tomcat server and Spring MVC without you writing the setup.

Add this if they push: You can override or exclude it, for example @SpringBootApplication(exclude = DataSourceAutoConfiguration.class).

6. What are Spring Boot starters?

Say it like this: Starters are ready-made dependency bundles. Instead of adding many libraries one by one, you add one starter, such as spring-boot-starter-web or spring-boot-starter-data-jpa, and it brings in compatible versions of everything needed.

7. What is the embedded server in Spring Boot?

Say it like this: It’s a server such as Tomcat packaged inside your application, so you can run the app as a simple JAR with java -jar without installing a separate server. Tomcat is the default, and you can switch to Jetty or Undertow.

8. How do you change the server port?

Say it like this: Set server.port in application.properties, for example server.port=9090.

PART 2: DEPENDENCY INJECTION AND BEANS (Questions 9 to 14)

9. What is Dependency Injection?

Say it like this: Dependency Injection means an object receives the other objects it needs from outside instead of creating them itself. Spring creates and manages those objects, called beans, and injects them where needed. This makes the code loosely coupled and easier to test.

10. What are the types of dependency injection?

Say it like this: Constructor injection, setter injection and field injection. Constructor injection is generally recommended because dependencies are clear, can be final and are easy to test.

java

@Service
public class StudentService {

    private final StudentRepository repository;

    public StudentService(StudentRepository repository) {   // constructor injection
        this.repository = repository;
    }
}

@Service
public class StudentService {

    private final StudentRepository repository;

    public StudentService(StudentRepository repository) {   // constructor injection
        this.repository = repository;
    }
}

@Service
public class StudentService {

    private final StudentRepository repository;

    public StudentService(StudentRepository repository) {   // constructor injection
        this.repository = repository;
    }
}

Avoid: Saying “field injection with @Autowired is best.” It works, but it’s harder to test.

11. What is a bean?

Say it like this: A bean is an object that is created, managed and wired by the Spring container.

12. What’s the difference between @Component, @Service, @Repository and @Controller?

Say it like this: All four mark a class as a Spring-managed bean. @Component is the generic one. @Service marks business logic, @Repository marks the data access layer and also translates database exceptions, and @Controller marks a web controller. Using the right one makes the code clearer.

13. What are bean scopes?

Say it like this: The default scope is singleton, meaning one instance per container. Others include prototype (a new instance each time), and web scopes such as request and session.

14. How do you resolve a conflict when two beans have the same type?

Say it like this: Use @Primary to mark a default bean, or @Qualifier("beanName") to choose a specific one at the injection point.

PART 3: REST CONTROLLERS (Questions 15 to 21)

15. What’s the difference between @Controller and @RestController?

Say it like this: @Controller is used to return views, such as HTML pages. @RestController combines @Controller and @ResponseBody, so every method returns data, usually JSON, directly in the response body.

16. Explain the common request mapping annotations.

Say it like this: @GetMapping, @PostMapping, @PutMapping, @DeleteMapping and @PatchMapping map HTTP methods to handler methods, and @RequestMapping can define a base path for the class.

17. What’s the difference between @PathVariable, @RequestParam and @RequestBody?

java

@RestController
@RequestMapping("/api/students")
public class StudentController {

    private final StudentService service;

    public StudentController(StudentService service) {
        this.service = service;
    }

    @GetMapping("/{id}")
    public Student getById(@PathVariable Long id) {
        return service.findById(id);
    }

    @GetMapping
    public List<Student> search(@RequestParam(required = false) String name) {
        return service.search(name);
    }

    @PostMapping
    public ResponseEntity<Student> create(@Valid @RequestBody Student student) {
        return ResponseEntity.status(HttpStatus.CREATED).body(service.save(student));
    }
}

@RestController
@RequestMapping("/api/students")
public class StudentController {

    private final StudentService service;

    public StudentController(StudentService service) {
        this.service = service;
    }

    @GetMapping("/{id}")
    public Student getById(@PathVariable Long id) {
        return service.findById(id);
    }

    @GetMapping
    public List<Student> search(@RequestParam(required = false) String name) {
        return service.search(name);
    }

    @PostMapping
    public ResponseEntity<Student> create(@Valid @RequestBody Student student) {
        return ResponseEntity.status(HttpStatus.CREATED).body(service.save(student));
    }
}

@RestController
@RequestMapping("/api/students")
public class StudentController {

    private final StudentService service;

    public StudentController(StudentService service) {
        this.service = service;
    }

    @GetMapping("/{id}")
    public Student getById(@PathVariable Long id) {
        return service.findById(id);
    }

    @GetMapping
    public List<Student> search(@RequestParam(required = false) String name) {
        return service.search(name);
    }

    @PostMapping
    public ResponseEntity<Student> create(@Valid @RequestBody Student student) {
        return ResponseEntity.status(HttpStatus.CREATED).body(service.save(student));
    }
}

18. What is ResponseEntity?

Say it like this: ResponseEntity lets you control the whole HTTP response: the body, the status code and the headers.

19. How do you validate input in Spring Boot?

Say it like this: Add the validation starter, put constraints such as @NotBlank, @Email and @Size on the fields, and use @Valid on the request body. If validation fails, Spring throws an exception that you can handle globally.

java

public class Student {
    @NotBlank(message = "Name is required")
    private String name;

    @Email(message = "Enter a valid email")
    private String email;
    // getters and setters
}

public class Student {
    @NotBlank(message = "Name is required")
    private String name;

    @Email(message = "Enter a valid email")
    private String email;
    // getters and setters
}

public class Student {
    @NotBlank(message = "Name is required")
    private String name;

    @Email(message = "Enter a valid email")
    private String email;
    // getters and setters
}

20. How do you handle exceptions globally?

Say it like this: With @ControllerAdvice (or @RestControllerAdvice) and @ExceptionHandler methods, which return clean error responses in one place instead of try-catch blocks everywhere.

java

@RestControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(ResourceNotFoundException.class)
    public ResponseEntity<Map<String, String>> handleNotFound(ResourceNotFoundException ex) {
        return ResponseEntity.status(HttpStatus.NOT_FOUND)
                .body(Map.of("error", ex.getMessage()));
    }
}

@RestControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(ResourceNotFoundException.class)
    public ResponseEntity<Map<String, String>> handleNotFound(ResourceNotFoundException ex) {
        return ResponseEntity.status(HttpStatus.NOT_FOUND)
                .body(Map.of("error", ex.getMessage()));
    }
}

@RestControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(ResourceNotFoundException.class)
    public ResponseEntity<Map<String, String>> handleNotFound(ResourceNotFoundException ex) {
        return ResponseEntity.status(HttpStatus.NOT_FOUND)
                .body(Map.of("error", ex.getMessage()));
    }
}

21. Which HTTP status codes should you return?

Say it like this: 200 for success, 201 for created, 204 for no content, 400 for a bad request, 401 for unauthenticated, 403 for forbidden, 404 for not found and 500 for a server error.

PART 4: SPRING DATA JPA AND DATABASE (Questions 22 to 26)

22. What is Spring Data JPA?

Say it like this: It’s a Spring module that reduces boilerplate for database access. You define an interface that extends JpaRepository, and Spring generates the implementation for common operations such as save, find and delete.

java

public interface StudentRepository extends JpaRepository<Student, Long> {

    List<Student> findByCourse(String course);              // derived query

    @Query("SELECT s FROM Student s WHERE s.email = :email")
    Optional<Student> findByEmailAddress(@Param("email") String email);
}

public interface StudentRepository extends JpaRepository<Student, Long> {

    List<Student> findByCourse(String course);              // derived query

    @Query("SELECT s FROM Student s WHERE s.email = :email")
    Optional<Student> findByEmailAddress(@Param("email") String email);
}

public interface StudentRepository extends JpaRepository<Student, Long> {

    List<Student> findByCourse(String course);              // derived query

    @Query("SELECT s FROM Student s WHERE s.email = :email")
    Optional<Student> findByEmailAddress(@Param("email") String email);
}

23. What’s the difference between CrudRepository and JpaRepository?

Say it like this: CrudRepository offers basic CRUD operations. JpaRepository extends it and adds JPA-specific features such as flushing and batch operations, along with paging and sorting through PagingAndSortingRepository.

24. What does @Transactional do?

Say it like this: It makes a method run inside a database transaction. If everything succeeds the changes are committed, and if a runtime exception occurs the transaction is rolled back by default.

25. How do you do pagination?

Say it like this: Pass a Pageable to the repository method, for example PageRequest.of(0, 10), and receive a Page<T> back, which contains the data and the page information.

26. What is the N+1 problem?

Say it like this: It happens when loading a list of entities triggers one query for the list and then one extra query per item to load a related entity. It slows things down, and you can reduce it with fetch joins, entity graphs or proper fetch strategies.

PART 5: CONFIGURATION, SECURITY AND PRODUCTION (Questions 27 to 30)

27. What is application.properties and how do profiles work?

Say it like this: It’s the main configuration file where you set values such as the port and database URL. Profiles let you keep different settings for different environments, for example application-dev.properties and application-prod.properties, and activate one with spring.profiles.active=dev.

properties

# application.properties
server.port=8080
spring.datasource.url=jdbc:mysql://localhost:3306/studentdb
spring.datasource.username=root
spring.datasource.password=${DB_PASSWORD}
spring.jpa.hibernate.ddl-auto=update
spring.profiles.active=dev

# application.properties
server.port=8080
spring.datasource.url=jdbc:mysql://localhost:3306/studentdb
spring.datasource.username=root
spring.datasource.password=${DB_PASSWORD}
spring.jpa.hibernate.ddl-auto=update
spring.profiles.active=dev

# application.properties
server.port=8080
spring.datasource.url=jdbc:mysql://localhost:3306/studentdb
spring.datasource.username=root
spring.datasource.password=${DB_PASSWORD}
spring.jpa.hibernate.ddl-auto=update
spring.profiles.active=dev

Avoid: committing real passwords to GitHub. Use environment variables.

28. What is Spring Boot Actuator?

Say it like this: Actuator adds production-ready endpoints for monitoring and managing your application, such as /actuator/health and metrics, which show the app’s status and health.

29. How would you secure a Spring Boot REST API?

Say it like this: I’d use Spring Security. Users log in with credentials, the server issues a token such as a JWT, and the client sends it in the Authorization header with every request. A filter validates the token, and I’d restrict endpoints by role. Passwords are stored hashed, for example with BCrypt, never as plain text.

30. What is the difference between authentication and authorisation?

Say it like this: Authentication checks who you are, for example by validating login credentials. Authorisation checks what you’re allowed to do after you’re identified, for example whether you can access an admin endpoint.

PART 6: TRICKY FOLLOW-UP QUESTIONS INTERVIEWERS LOVE

PART 7: HOW TO EXPLAIN YOUR SPRING BOOT PROJECT

Interviewers almost always follow the theory questions with “tell me about your project.” Here’s a pattern you can adapt.

“My project is a student management system built with Spring Boot and MySQL. I structured it into controller, service and repository layers. I used Spring Data JPA for database access, @Valid for input validation and a global exception handler for clean error responses. The trickiest part was preventing duplicate email registrations, which I solved with a unique constraint and a check in the service layer. If I had more time, I’d add JWT authentication and pagination.”

Pattern: what it does, how it’s built, one real challenge, one improvement.

PART 8: MISTAKES THAT COST FRESHERS MARKS

PART 9: LAST-MINUTE REVISION SHEET

PART 10: A 5-DAY PREPARATION PLAN

PART 11: HOW VIBRANTMINDS HELPS

VibrantMinds Technologies Pvt. Ltd. trains freshers in Pune for Java full stack roles, with Spring Boot and REST APIs as part of the programme.

• Hands-on Spring Boot training: The Full Stack Java course covers Core Java, OOP, JDBC, SQL, Spring Boot, REST APIs and front-end basics with project work, so you have something real to talk about in interviews. Please check the candidate portal for the latest syllabus.

• Interview preparation: Aptitude, communication and interview preparation are part of the programme, so you practise explaining concepts and projects aloud.

• Placement support: The placement pipeline includes screening, drive coordination and interview support. Check the campus-drives portal at https://candidates.vibrantminds.in/ for current openings.

• Honesty first: VibrantMinds offers placement support, not a guaranteed job, and no legitimate recruiter should ask you to pay to be interviewed.

VibrantMinds works as a talent ecosystem connecting candidates, colleges and companies, with 1900+ partner colleges and 600+ hiring companies. Learn more on the official website: https://vibrantminds.in/

PART 12: VIBRANTMINDS COURSES AT A GLANCE

Fees, syllabus and batch dates are on https://candidates.vibrantminds.in/. Please confirm them directly before enrolling.

PART 13: THE VIBRANTMINDS PLACEMENT PIPELINE: SIX STEPS

PART 14: REAL OUTCOMES: WHAT TO EXPECT AND WHAT NOT TO

Past students have shared positive feedback about the training and support, and have gone on to roles at companies such as Aress Software and Education Technologies, Saama Technologies and Three M Software. Results vary by candidate, skill level, effort and market conditions, so please confirm details directly with the VibrantMinds team. No one can honestly promise a guaranteed job.

PART 15: JOIN THE VIBRANTMINDS WHATSAPP GROUPS FOR FRESHER JOB AND DRIVE ALERTS

Fresher openings, campus drives and walk-in interviews are shared here as they come in. Join whichever group has space; all three carry the same type of updates.

• VibrantMinds Fresher IT Jobs, Group 1: https://chat.whatsapp.com/CUCS1derlmTFee2c9dyUHd

• VibrantMinds Fresher IT Jobs, Group 2: https://chat.whatsapp.com/FvMf1fGYQYnHppQ8AwFX40

• VibrantMinds Fresher IT Jobs, Group 3: https://chat.whatsapp.com/I7RNnGMkb2L8S8HibdyWpQ

Never pay to apply. Legitimate recruiters do not charge candidates for tests, interviews or offer letters. Do not share sensitive personal or financial details in any group chat.

PART 16: VISIT OR CONTACT VIBRANTMINDS IN PUNE

• Company: VibrantMinds Technologies Pvt. Ltd.

• Address: Viva Academy Building, Warje, Pune, Maharashtra 411052

• Phone: +91 95035 79517

• Email: support@vibrantmindstech.com

• Website: https://vibrantminds.in/

• Candidate portal and courses: https://candidates.vibrantminds.in/

PART 17: FREQUENTLY ASKED QUESTIONS

What are the most common Spring Boot interview questions for freshers?
The most common ones are: What is Spring Boot? What is the difference between Spring and Spring Boot? What does @SpringBootApplication do? What is auto-configuration? What is the difference between @Controller and @RestController? How does dependency injection work? and How do you handle exceptions globally?

How should a fresher prepare for a Spring Boot interview?
Learn the core annotations, build one complete REST API project with a database, practise explaining each layer aloud and do at least one mock interview. Understanding beats memorising.

Is Spring Boot enough to get a Java developer job?
It’s a major part of most Java full stack roles, but you also need Core Java, OOP, collections, SQL and good project explanations. Interviewers test the whole combination.

What is the difference between @RestController and @Controller?
@Controller typically returns view names for web pages, while @RestController returns data directly, usually JSON, because it includes @ResponseBody.

What is dependency injection in Spring Boot?
It’s a way for Spring to provide an object’s dependencies from outside, so classes don’t create them manually. Constructor injection is the recommended style.

Do I need to learn Spring Security as a fresher?
Basic understanding of authentication, authorisation and JWT is useful, and some interviewers ask about it. Deep expertise isn’t usually expected from freshers.

What database should I use with Spring Boot for practice?
MySQL or PostgreSQL are common choices, and SQL knowledge is often tested alongside Spring Boot.

What is Spring Data JPA used for?
It simplifies database access by generating repository implementations, so you write less code for common operations like save, find and delete.

How long does it take to learn Spring Boot?
If your Core Java and SQL are comfortable, many learners need a few weeks of focused practice to build a basic REST API project. Your starting level matters more than any fixed timeline.

Where can I learn Spring Boot in Pune?
VibrantMinds Technologies offers Full Stack Java training in Pune that includes Spring Boot and REST APIs, along with interview preparation and placement support. VibrantMinds does not guarantee a job, so please confirm the current syllabus and details directly with the team.

PART 18: FINAL CHECKLIST BEFORE YOUR INTERVIEW

• ☐ I can explain Spring vs Spring Boot in 30 seconds

• ☐ I know what @SpringBootApplication contains

• ☐ I can explain dependency injection and why constructor injection is preferred

• ☐ I can describe @RestController, @PathVariable, @RequestParam and @RequestBody

• ☐ I can explain @Transactional and global exception handling

• ☐ I have one project I can explain from controller to database

• ☐ I’ve practised answering aloud at least once

If most of those are ticked, you’re in good shape. And if you’re in Pune and want guided Spring Boot training with interview practice and placement support, visit https://vibrantminds.in/, check the candidate portal at https://candidates.vibrantminds.in/, and join the WhatsApp groups above for the next drive.