Constructor-based Dependency Injection

Snippet

Constructor-based Dependency Injection

Constructor injection is the recommended way to handle dependencies. It ensures that required fields are final and the bean is fully initialized upon creation.

snippet.java

java

@Component
public class NotificationManager {
    private final EmailService emailService;
 
    public NotificationManager(EmailService emailService) {
        this.emailService = emailService;
    }
}

spring

Breakdown

private final EmailService emailService;

Declares an immutable dependency.

public NotificationManager(EmailService emailService)

Spring automatically finds and injects the required bean through the constructor.

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Constructor-based Dependency Injection

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