com.thoughtworks.xstream.mapper.CannotResolveClassException

com.thoughtworks.xstream.mapper.CannotResolveClassException

I am getting this exception while converting from xml to object.
"cardHolder (com.thoughtworks.xstream.mapper.CannotResolveClassException)"
My class is given below:
@XmlRootElement
public class CardHolder {
String transactionType;
String cardNumber;
//cons..
//getters and setters
}