Validate credit card and get card type by java code

import org.apache.commons.validator.GenericValidator

def getCreditCardType(String cardNumber) throws AutobillException {
    cardNumber = "" + cardNumber;
    cardNumber = cardNumber.trim();
    cardNumber = cardNumber.replaceAll("\\D+", "");
    if(!GenericValidator.isCreditCard(cardNumber)) {
        throw new InvalidPropertyException("cardNumber");
    }
    if(cardNumber.matches(("^4[0-9]{12}(?:[0-9]{3})?\$"))) {
        return "VISA";
    } else if(cardNumber.matches(("^5[1-5][0-9]{14}\$"))) {
        return "MASTERCARD";
    } else if(cardNumber.matches(("^3[47][0-9]{13}\$"))) {
        return "AMEX";
    } else if(cardNumber.matches(("^3(?:0[0-5]|[68][0-9])[0-9]{11}\$"))) {
        return "DINERS";
    } else if(cardNumber.matches(("^6(?:011|5[0-9]{2})[0-9]{12}\$"))) {
        return "DISCOVER";
    } else if(cardNumber.matches(("^(?:2131|1800|35\\d{3})\\d{11}\$"))) {
        return "JCB";
    }
    return null;
}

Credit card validation using php

<?php
define("CARD_TYPE_MASTERCARD","CARD_TYPE_MASTERCARD");
define("CARD_TYPE_VISA","CARD_TYPE_VISA");
define("CARD_TYPE_AEX","CARD_TYPE_AEX");
define("CARD_TYPE_DINERS","CARD_TYPE_DINERS");
define("CARD_TYPE_DISCOVER","CARD_TYPE_DISCOVER");
define("CARD_TYPE_JCB","CARD_TYPE_JCB");

function getCardType($cardNumber){
    $cardNumber = preg_replace('/\D/', '', $cardNumber);
    $len = strlen($cardNumber);
    if ($len < 15 || $len > 16) {
        return null;
    } else {
        switch($cardNumber) {
            case(preg_match ('/^4/', $cardNumber) >= 1):
                return CARD_TYPE_VISA;
            case(preg_match ('/^5[1-5]/', $cardNumber) >= 1):
                return CARD_TYPE_MASTERCARD;
            case(preg_match ('/^3[47]/', $cardNumber) >= 1):
                return CARD_TYPE_AEX;
            case(preg_match ('/^3(?:0[0-5]|[68])/', $cardNumber) >= 1):
                return CARD_TYPE_DINERS;
            case(preg_match ('/^6(?:011|5)/', $cardNumber) >= 1):
                return CARD_TYPE_DISCOVER;
            case(preg_match ('/^(?:2131|1800|35\d{3})/', $cardNumber) >= 1):
                return CARD_TYPE_JCB;
            default:
                return null;
                break;
        }
    }
    return null;
}
?>