Validate thai ID card

IDCardUtil.java

public class IDCardUtil {

    public static boolean isValid(String idCard){
        if (idCard.length()!=13){
            return false;
        }
        int sum = 0;
        for (int i = 0; i < 12; i++) {
            sum += Character.getNumericValue(idCard.charAt(i))*(13-i);
        }
        return (11-sum%11)%10 == Character.getNumericValue(idCard.charAt(12));

    }
}