Why annotations drive Spring Boot in Spring Boot - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to mark the class as a Spring Boot application.

Spring Boot

@[1]
public class MyApp {
    public static void main(String[] args) {
        SpringApplication.run(MyApp.class, args);
    }
}

Drag options to blanks, or click blank then click option'

AComponent

BSpringBootApplication

CService

DRepository

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Component instead of @SpringBootApplication

Forgetting to add any annotation on the main class

The @SpringBootApplication annotation marks the main class as the entry point for Spring Boot. It enables auto-configuration and component scanning.

2fill in blank

medium

Complete the code to inject a service bean into the controller using annotation.

Spring Boot

@RestController
public class MyController {
    private final MyService service;

    public MyController([1] MyService service) {
        this.service = service;
    }
}

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A@Service

B@Inject

C@Component

D@Autowired

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Service instead of @Autowired on constructor parameter

Not annotating the constructor parameter at all

The @Autowired annotation tells Spring to inject the service bean into the constructor.

3fill in blank

hard

Fix the error in the code by completing the annotation to define a REST endpoint.

Spring Boot

@RestController
public class HelloController {

    @[1]("/hello")
    public String sayHello() {
        return "Hello, World!";
    }
}

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APostMapping

BRequestMapping

CGetMapping

DService

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Service instead of a mapping annotation

Using @PostMapping for a GET endpoint

The @GetMapping annotation maps HTTP GET requests to the method, defining a REST endpoint.

4fill in blank

hard

Fill both blanks to define a service class and mark it as a Spring bean.

Spring Boot

[1]
public class UserService {

    public String getUser() {
        return "User1";
    }
}

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A@Service

B@Repository

C@Component

D@Controller

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Controller or @Repository incorrectly for service classes

Not annotating the class at all

The @Service annotation marks the class as a service bean for Spring to manage.

5fill in blank

hard

Fill all three blanks to create a REST controller with a GET endpoint that returns a greeting.

Spring Boot

@[1]
public class GreetingController {

    @[2]("/greet")
    public String greet() {
        return [3];
    }
}

Drag options to blanks, or click blank then click option'

ARestController

BGetMapping

C"Hello from Spring Boot!"

DService

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Controller instead of @RestController

Using @PostMapping instead of @GetMapping

Returning a variable instead of a string literal

The @RestController marks the class as a REST controller. @GetMapping maps GET requests to the method. The method returns a greeting string.