How do you make a deep copy of an object in Java?

private static final XStream XSTREAM = new XStream();
...

Object newObject = XSTREAM.fromXML(XSTREAM.toXML(obj));

ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream(bos);
oos.writeObject(object);
oos.flush();
oos.close();
bos.close();
byte [] byteData = bos.toByteArray();

ByteArrayInputStream bais = new ByteArrayInputStream(byteData);
(Object) object = (Object) new ObjectInputStream(bais).readObject();

if (instance1 == instance2) {
    // same instance
}
if (instance1.equals(instance2)) {
    // same value. maybe or maybe not same instance.
}

import com.thoughtworks.xstream.XStream;

public class deepCopy {

    private static  XStream xstream = new XStream();


    //serialize with Xstream them deserialize ...

    public static Object deepCopy(Object obj){


        return xstream.fromXML(xstream.toXML(obj));


    }



}