Hackforge Academy

Category: React • Beginner

Published on 06 Apr 2026

Explanation

IoC (Inversion of Control) is a design principle where the control of object creation and dependency management is transferred from the programmer to the Spring framework. Instead of manually creating objects, Spring automatically manages them.

Code Example

// Without IoC (manual object creation)
StudentService service = new 
StudentService();

Explanation

With IoC in Spring Boot, objects are created and managed by the Spring Container automatically using annotations like @Component, @Service, @Repository, and @Controller.

Code Example

@Service
public class StudentService {

}

Explanation

Spring Container is responsible for creating objects (beans), managing their lifecycle, and injecting dependencies wherever required.

Code Example

@Component
public class CourseService {

}

Explanation

Dependency Injection (DI) is the implementation of IoC in Spring Boot. Dependencies are injected automatically instead of being manually created.

Code Example

@Service
public class StudentService {

    private CourseService courseService;

    public StudentService(
CourseService courseService) {
        this.courseService = courseService;
    }
}

Explanation

@Autowired annotation is commonly used to inject dependencies automatically from the Spring Container.

Code Example

@Service
public class StudentService {

    @Autowired
    private CourseService courseService;
}

Explanation

IoC improves code flexibility, reduces tight coupling between classes, and makes applications easier to maintain. It is widely used in Spring Boot applications such as REST APIs, student systems, and training platforms like the ones you build 🚀.

Code Example

@RestController
public class StudentController {

private final StudentService studentService;

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