SOLID Principles in Spring Boot: A Comprehensive Guide

Thank you so much, and sorry for the very late reply.

You can initialize it in multiple ways:

1- Constructor injection:

private final PaymentService creditCardPaymentService; private final PaymentService payPalPaymentService;

@Autowired public PaymentController(CreditCardPaymentService creditCardPaymentService, PayPalPaymentService payPalPaymentService) { this.creditCardPaymentService = creditCardPaymentService; this.payPalPaymentService = payPalPaymentService; }

2- With qualifiers:

@Qualifier("payPalPaymentService") public class PayPalPaymentService extends PaymentService {

and then in your controller or other service:

private final PaymentService creditCardPaymentService; private final PaymentService payPalPaymentService;

@Autowired public PaymentController(@Qualifier("creditCardPaymentService") PaymentService creditCardPaymentService, @Qualifier("payPalPaymentService") PaymentService payPalPaymentService) { this.creditCardPaymentService = creditCardPaymentService; this.payPalPaymentService = payPalPaymentService; }