问程序无法在对象的更新信息之后执行compareTo功能

EN

    @Override
public int compareTo(Product o) {
    if (this.getQuantity() < o.getQuantity()) {
        return 1;
    }
    if (this.getQuantity() == o.getQuantity()) {
        return this.unitPrice-o.unitPrice;
    }
    return -1;
}

    public void updateInfo() {
    Scanner sc = new Scanner(System.in);
    String id, productName, quantity, unitPrice, numberForAvail;
    while (true) {
        try {
            System.out.print("Input products's id: ");
            id = sc.nextLine().toUpperCase();
            if (id.isEmpty()) {
                this.id = this.id;
            } else {
                if (!id.matches(letter_regEx) || id.length() < 5) {
                    throw new Exception();
                }
                this.id = id;
            }
            break;
        } catch (Exception e) {
            System.out.println("ID must be character and lenght > 5");
        }
    }

    while (true) {
        try {
            System.out.print("Input prodct's name: ");
            productName = sc.nextLine().toUpperCase();
            if (productName.isEmpty()) {
                this.productName = this.productName;
            } else {
                if (!productName.matches(letter_regEx)) {
                    throw new Exception();
                }
                this.productName = productName;
            }
            break;
        } catch (Exception e) {
            System.out.println("Invalid name");
        }
    }
    while (true) {
        try {
            System.out.print("Input Unit Price: ");
            unitPrice = sc.nextLine();
            if (unitPrice.isEmpty()) {
                this.unitPrice = this.unitPrice;
            } else {
                if (!unitPrice.matches("^([1-9][0-9]{0,3}|10000)$")) {
                    throw new Exception();
                }
                this.unitPrice = Integer.parseInt(unitPrice);
            }
            break;
        } catch (Exception e) {
            System.out.println("Unit price must be > 0 and < 10000");
        }
    }
    while (true) {
        try {
            System.out.print("Input quantity: ");
            quantity = sc.nextLine();
            if (quantity.isEmpty()) {
                this.quantity = this.quantity;
            } else {
                if (!quantity.matches("^([1-9][0-9]{0,2}|1000)$")) {
                    throw new Exception();
                }
                this.quantity = Integer.parseInt(quantity);
            }
            break;
        } catch (Exception e) {
            System.out.println("Quantity must be > 0 and < 1000");
        }
    }

    while (true) {
        try {
            System.out.print("Input status [0(not available)/ 1 (available)]: ");
            numberForAvail = sc.nextLine();
            if (numberForAvail.isEmpty()) {
                this.numberForAvail = this.numberForAvail;
            } else {
                if (!numberForAvail.matches("^[01]$")) {
                    throw new Exception();
                }
                this.numberForAvail = Integer.parseInt(numberForAvail);
                break;
            }
        } catch (Exception e) {
            System.out.println("Status must 0 for NOT AVAILABLE and 1 for AVAILABLE");
        }
    }
    if (this.numberForAvail == 0) {
        status = "Not available";
    } else {
        status = "Available";
    }

}