@SPI("default") public interface OrderService { void processOrder(Order order); } @SPI("default") public class DefaultOrderService implements OrderService { public void processOrder(Order order) { } } OrderService orderService = ExtensionLoader.getExtensionLoader(OrderService.class).getExtension("default"); orderService.processOrder(order); @SPI("default") public interface OrderService { void processOrder(Order order); } @SPI("default") public class DefaultOrderService implements OrderService { public void processOrder(Order order) { } } OrderService orderService = ExtensionLoader.getExtensionLoader(OrderService.class).getExtension("default"); orderService.processOrder(order);