converting xml file into Object using xstream but if a Variable not present in xml file but in Object then it assign default value to it how to change

this is xml file

<com.baeldung.pojo.Customer>
<firstName>John</firstName>
<lastName>Doe</lastName>
<dob>1986-02-14 03:46:16.381 UTC</dob>
</com.baeldung.pojo.Customer>

this is java object

public class Customer {
private String firstName;
private String lastName;
private Date dob;
private isMale;
// standard setters and getters
}

isMale not in xml file so when i convert xml file into Customer Object it assign isMale=false but i want it to assign it true by default only for once

conversion code

public static <A> A fromXML(Class<A> c, File file) {
XStream xStream = new XStream();
// Avoid "Security framework of XStream not initialized, XStream is probably vulnerable." warning.
XStream.setupDefaultSecurity(xStream);
xStream.allowTypesByWildcard(new String[] {
"configurationFiles.**",
"java.awt.Dimension"
});
xStream.ignoreUnknownElements();
InputStream inputStream = null;
Reader reader = null;
try {
inputStream = new java.io.FileInputStream(file);
//System.out.println("inside fromXml  try");
reader = new InputStreamReader(inputStream, Charset.forName("UTF-8"));
Object object = xStream.fromXML(reader);
//			boolean isMarriedExists = ((Object) xStream).getUnmarshaller().getContext().hasField("isMarried");
// System.out.println(c+"--"+object);
if (c.isInstance(object)) {
return (A)object;
}
} 
catch (Exception exp) {
//System.out.println("inside fromXml  catch");
exp.printStackTrace();
//log.error(null, exp);
} catch (java.lang.Error err) {
//System.out.println("inside fromXml  catch");
err.printStackTrace();
//log.error(null, err);
} finally {
close(reader);
close(inputStream);
}
return null;
}

using above mention function and converting the xml file using xStream.

File f = new File("customer.xml");
MainFrameXmlOptions mainFrameOptions=null;
if(f.exists())
mainFrameOptions = fromXML(MainFrameXmlOptions.class, f);

Try adding ctor

public Customer() {
super();
isMale = true;
}

You will need to get XStream to honour that with

XStream xStream = new XStream(new com.thoughtworks.xstream.converters.reflection.PureJavaReflectionProvider());