Project structure walkthrough in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the main Spring Boot application class.

Spring Boot

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

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

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

ASpringBootApp

BMainApp

CApplication

DMyApp

Attempts:

3 left

💡 Hint

Common Mistakes

Using a class name that does not match in the run method.

Forgetting the @SpringBootApplication annotation.

The main class is usually named Application or similar. Here, 'Application' is the correct class name used in the run method.

2fill in blank

medium

Complete the code to declare a REST controller in Spring Boot.

Spring Boot

import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.GetMapping;

@RestController
public class HelloController {
    @GetMapping("/hello")
    public String [1]() {
        return "Hello, World!";
    }
}

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AgetHello

Bhello

Cgreet

DsayHello

Attempts:

3 left

💡 Hint

Common Mistakes

Using method names that do not reflect the HTTP method.

Missing the @GetMapping annotation.

The method name can be anything, but 'getHello' clearly indicates a GET request handler for /hello.

3fill in blank

hard

Fix the error in the Spring Boot application.properties file to set the server port.

Spring Boot

server.[1]=8081

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Aport

Bhost

Caddress

Durl

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'server.host' instead of 'server.port'.

Setting properties in the wrong file.

The correct property to set the server port is 'server.port'.

4fill in blank

hard

Fill both blanks to create a simple service class and inject it into a controller.

Spring Boot

import org.springframework.stereotype.Service;

@Service
public class [1] {
    public String getMessage() {
        return "Service message";
    }
}

import org.springframework.web.bind.annotation.RestController;
import org.springframework.beans.factory.annotation.Autowired;

@RestController
public class MessageController {

    private final [2] service;

    @Autowired
    public MessageController([2] service) {
        this.service = service;
    }

    public String showMessage() {
        return service.getMessage();
    }
}

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AMessageService

BMessageController

DHelloService

Attempts:

3 left

💡 Hint

Common Mistakes

Mismatching class names between service and controller.

Forgetting to annotate the service class with @Service.

The service class is named 'MessageService' and injected into the controller as the same type.

5fill in blank

hard

Fill all three blanks to define a Spring Data JPA repository interface.

Spring Boot

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface [1] extends JpaRepository<[2], [3]> {
}

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AUserRepository

BUser

CLong

DUserService

Attempts:

3 left

💡 Hint

Common Mistakes

Using service class names instead of repository names.

Incorrect generic types in JpaRepository.

The repository interface is named 'UserRepository', managing 'User' entities with 'Long' as ID type.