Question

I have an input xml and corresponding java classes as the following.

<Address>
  <name>name</name>
  <streetName>street</streetName>
<Address>

public class Address {
    private String name;
    //getter and setter here
}

public class Home extends Address {
    private String streetName;
    // getter and setter follows
}

And I tried to unmarshal the xml like the following

import com.thoughtworks.xstream.XStream;

public class Main {
    public static void main(String as[]) {
        XStream xstream = new XStream();
        String str = "<com.xstream.inheritance.Address> <name>name</name> <streetName>street</streetName>"
                + "</com.xstream.inheritance.Address>";
        Address address1 = (Address) xstream.fromXML(str);
        System.out.println(address1.getName());
    }
}

I got an exception saying
Exception in thread “main”

com.thoughtworks.xstream.converters.reflection.AbstractReflectionConverter$UnknownFieldException: No such field com.xstream.inheritance.Address.streetName
---- Debugging information ----
field               : streetName
class               : com.xstream.inheritance.Address
required-type       : com.xstream.inheritance.Address
converter-type      : com.thoughtworks.xstream.converters.reflection.ReflectionConverter
path                : /com.xstream.inheritance.Address/streetName
version             : null

Why did I get this exception?

Answer 1

The XML is missing the “class” attribute which would point to your extended class. So the output would be like this:

<com.xstream.inheritance.Address class="com.xstream.inheritance.Home">
 <name>name</name>
 <streetName>street</streetName>
</com.xstream.inheritance.Address>

This is done automatically by XStream.