Java

If you’ve ever swapped @Configuration for @Component on a Spring config class and thought “it’s basically the same thing”, this article is for you. They’re not the same. And the difference can silently break your application in ways that are hard to debug. Let’s walk through a real example. Sample setup for example: We have a simple payment system with two implementations of a PaymentService interface: public interface PaymentService { void pay(double amount); } public class PaypalPaymentService implements PaymentService { public void pay(double amount) { System.out.println("PAYPAL\nAmount: " + amount + " paid."); } } public class StripePaymentService implements PaymentService { public void pay(double amount) { System.out.println("STRIPE\nAmount: " + amount + " paid."); } } And an OrderService That depends on whichever PaymentService is active: ...