@Configuration vs @Component in SpringBoot: A Subtle But Critical Difference

Sat, 25 Apr 2026 11:32:43 +0530

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:

I Got Hacked

Sat, 25 Apr 2026 00:05:01 +0530

I made a rookie mistake.

I built a Telegram bot that fetches top stories from Lobste.rs — ones scoring above a threshold I set. Straightforward enough. The problem was deployment.

I’m not great at setting up servers, so I turned to AI for help. I don’t usually accept AI output blindly, but this time I did, and it gave me this:

# docker-compose.yml
services:
 db:
 image: mysql:8.0
 restart: unless-stopped
 environment:
 MYSQL_ROOT_PASSWORD: rootpassword
 MYSQL_DATABASE: ${MYSQL_DB:-lobster_bot}
 MYSQL_USER: ${MYSQL_USER:-lobster}
 MYSQL_PASSWORD: ${MYSQL_PASSWORD:-lobsterpassword}
 volumes:
 - mysql_data:/var/lib/mysql
 ports:
 - "3306:3306"

The bot ran fine for two days. Then the Telegram notifications stopped.

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@Configuration vs @Component in SpringBoot: A Subtle But Critical Difference

Sample setup for example:

I Got Hacked