Business logic in services in Spring Boot - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the role of a service class in Spring Boot?

A service class contains business logic. It acts as a middle layer between controllers and repositories, handling data processing and rules before saving or returning data.

beginner

Why should business logic not be placed in controllers or repositories?

Controllers should only handle HTTP requests and responses, while repositories manage data access. Putting business logic in services keeps code organized, easier to test, and maintainable.

beginner

How do you annotate a service class in Spring Boot?

Use the @Service annotation above the class. This tells Spring to treat it as a service component and manage it as a bean.

intermediate

What is a common pattern for calling a service from a controller?

The controller injects the service using @Autowired or constructor injection, then calls service methods to perform business logic before returning results.

intermediate

Give an example of business logic that belongs in a service.

Calculating discounts, validating user input beyond simple format checks, or deciding if a user can perform an action based on roles are examples of business logic for services.

What annotation marks a class as a service in Spring Boot?

A @Controller

B @Service

C @Repository

D @ComponentScan

The @Service annotation marks a class as a service component in Spring Boot.

Where should business logic primarily reside in a Spring Boot app?

A In the repository

B In the controller

C In the service layer

D In the application.properties file

Business logic belongs in the service layer to keep code organized and maintainable.

Which of these is NOT a responsibility of a service class?

A Handling HTTP requests

B Applying business rules

C Calling repositories

D Processing data

Handling HTTP requests is the controller's job, not the service's.

How does a controller typically get access to a service?

A By using @Autowired or constructor injection

B By creating a new instance with 'new'

C By calling static methods

D By reading from a config file

Spring injects service beans into controllers using @Autowired or constructor injection.

Which example is a good candidate for business logic in a service?

A Defining database schema

B Mapping a URL to a method

C Saving data to the database

D Checking if a user is allowed to access a feature

Deciding user permissions is business logic and belongs in the service layer.

Explain why business logic should be placed in service classes rather than controllers or repositories.

Think about keeping code organized and responsibilities clear.

Describe how a Spring Boot controller interacts with a service to perform business logic.

Focus on the flow from controller to service to repository.