modify the message based on the number of inputs

I have the following method which accepts a string of carcodes separated by a comma (it can be a single car code as well) and holdReason but my question is about carcodes.

For example, the carcodes can be like the following: "ABC1234, TYZ8765"

public PostReturn scan(String carcode, String holdReason) {
	PostReturn pr = new PostReturn();
	if (Utils.nullOrBlank(carcode)) {
		// cannot lookup
		pr.setErrorMsg("No carcode to lookup");
		return pr;
	}

	// trim it first/remove white spaces
	String[] carcodes = carcode.trim().split("\\s*,\\s*");
	for (String carId: carcodes) {
		Kitcarcode kb = Kitcarcode.parsecarcode(carId);
		if (kb == null) {
			// invalid carId
			pr.setErrorMsg(carId + " was invalid - could not be parsed");
			return pr;
		}
		// lookup the kit
		CarHandler cph = CarHandler.findByKitcarcode(kb);
		// mark it as on hold
		cph.setAttribute(CarHandler.PREPROCESSING_HOLD_DATE, Utils.getDateAsMDYYYY(new Date()));
		cph.setAttribute(CarHandler.PREPROCESSING_HOLD_REASON, holdReason);
		cph.storeChanges();
		carProcessing(kb, cph);
		// confirm msg
		pr.setSuccessMsg(kb + " is marked as on carprocessing hold for reason: " + holdReason);
	}
	return pr;
}

I'm mainly concerned about this line of code:
pr.setSuccessMsg(kb + " is marked as on carprocessing hold for reason: " + holdReason);

If there are multiple car codes, separated by comma, for example "ABC1234,TYZ8765"

the message printed by the above line of code is TYZ8765 is marked as on carprocessing hold for reason xyz. Since there are two carcodes , is it possible to print it like the following?

ABC1234 and TYZ8765 are marked as on carprocessing hod for reason xyz

It appears that the reason the message being printed only contains the last carcode is because the for-loop it's within, will simply over-write the previous pr.setSuccessMsg call during each iteration.

Since pr and holdReason are not changed within the for-loop, you can place it after the for-loop.

Additionally, from within the for-loop, you can populate a String value with the kb values.

We'll utilize the for-loop to increment a count value.
This will be used to determine if our strings value is being populated with 1, 2, or more kb values—which will determine if our strings value should contain commas or an "and".

We can further use the count value, after the for-loop is exited, to determine if we should be using "is", or "and".

The strings value is then used as the message sent to the setSuccessMsg method.

PostReturn pr = new PostReturn();
if (Utils.nullOrBlank(carcode)) {
    // cannot lookup
    pr.setErrorMsg("No carcode to lookup");
    return pr;
}
// trim it first/remove white spaces
String[] carcodes = carcode.trim().split("\\s*,\\s*");
StringBuilder strings = new StringBuilder();
int count = 0, length = carcodes.length;
for (String carId : carcodes) {
    Kitcarcode kb = Kitcarcode.parsecarcode(carId);
    if (kb == null) {
        // invalid carId
        pr.setErrorMsg(carId + " was invalid - could not be parsed");
        return pr;
    }
    // lookup the kit
    CarHandler cph = CarHandler.findByKitcarcode(kb);
    // mark it as on hold
    cph.setAttribute(CarHandler.PREPROCESSING_HOLD_DATE, Utils.getDateAsMDYYYY(new Date()));
    cph.setAttribute(CarHandler.PREPROCESSING_HOLD_REASON, holdReason);
    cph.storeChanges();
    carProcessing(kb, cph);
    if (count != 0) {
        if (length > 2) strings.append(", ");
        if (count == length - 1) {
            if (count == 1) strings.append(' ');
            strings.append("and ");
        }
    }
    strings.append(kb);
    count++;
}
strings.append(count == 1 ? " is " : " are ");
strings.append("marked as on carprocessing hold for reason: ");
strings.append(holdReason);
// confirm msg
pr.setSuccessMsg(strings.toString());
return pr;

As an example, printing the strings value would yield a similar output.

ABC123, DEF456, and GHI789 are marked as on carprocessing hold for reason: 
ABC123 and DEF456 are marked as on carprocessing hold for reason: 
ABC123 is marked as on carprocessing hold for reason: