I've scenario to validate given input param is empty or not, I've list of fields with datatype **string** and **date** - `productId,productName,productType,productRating,productSellDate and productReturnDate`

I want to check these input params are `null` or `empty` or `blank` for each field and if any one of the field is `empty` or `blank` or `null` - it should throw `NullPointerException` with field name.

Please find my code below - since I'm new to Java please apologize for the coding standard. I don't know how to get the field name which has `empty` or `null` when I throw `NullPointerException`

And I'm calling `validate` and `validateDate` for each string, is there any option to validate all these param in one go?

Please suggest if there is any better way of writing the below piece of code. Appreciated your help in advance! Thanks.

```
import java.util.Date;

public class Test {

    public static void main(String[] args) {
        String productId = "";
        String productName = "Apple";
        String productType = "Electronics";
        String productRating = "Good";
        Date productSellDate = new Date();
        Date productReturnDate = new Date();

        System.out.println(validate(productId));
        System.out.println(validate(productName));
        System.out.println(validate(productType));
        System.out.println(validate(productRating));

        System.out.println(validateDate(productSellDate));
        System.out.println(validateDate(productReturnDate));

    }

    private static String validate(String s) {
        if (s.isBlank() || s.isEmpty()) {
            throw new NullPointerException("input param is empty"); // how to get the string field name which is empty or null or blank
        } else {
            return "valid";
        }
    }

    private static String validateDate(Date d) {
        if (d == null) {
            throw new NullPointerException("sell or return date is empty"); // how to get the date field name which is empty or null or blank
        } else {
            return "date is valid";
        }
    }
}

```