Phát hiện chuỗi bị thiếu

public class CoffeeSalesExample {
    private record CoffeeSales(LocalDate date, String coffeeName,
            String paymentMethod, Integer quantity, Double amount) {
    }

    public static void main(String[] args) {
		CoffeeSales sale = new CoffeeSales(LocalDate.of(2024, 3, 1), null, " ", 1, 6.26);

		// Return coffeeName with a default if null
		String coffeeName = ____.____(sale.coffeeName(), "[No coffee name]");
		System.out.println("coffeeName: " + coffeeName);

        // Check if paymentMethod is empty or whitespace
        if (____.____(sale.paymentMethod())) {
            System.out.println("Payment method cannot be empty or whitespace");
        }
    }
}