Serializer SimpleXML just send first line

I have a problem trying to send a file xml between Android and a servlet with POST. I'm using (Simple XML) for the serializing.

My servlet do the response to Android:

Serializer serial = new Persister();
OutputStream o = response.getOutputStream();

MyXML myXML = new MyXML();
myXML.setMyElement("test");
serial.write(myXML, o);

It's supposed to send my xml directly to the client like this,

<MyXML>
  <MyElement>test</MyElement>
</MyXML> 

But it only sends the fir开发者_StackOverflowst line . Then, on the Android side gets this exception because it can't get the second line with the Element.

WARN/System.err(490): org.simpleframework.xml.core.ElementException: Element 'MyElement' does not have a match in class java.lang.Class at line -1

I can't understand why it only serialize the first line when i'm doing it with OutputStream because it works when i'm saving on files without sending it,

Serializer serial = new Persister();
File file = new File("MyPath");

MyXML myXML = new MyXML();
myXML.setMyElement("test");
serial.write(myXML, file);

I need to do it like that and not with bytes, just to avoid to set the response content length.

Many thanks,

EDIT: Adding MyXML.class

There is MyXML.class,

package part.myApp;

import org.simpleframework.xml.Element;
import org.simpleframework.xml.Root;

@Root(name="MyXML")
public class MyXML{

       @Element(name="MyElement")
       private String a;

       public void setMyElement(String a){
           this.a=a;
       }

       public String getMyElement() {
          return a;           
       }
}

Thanks.

---

Private access on 'a' might be a problem. Use the POJO options:

@Root(name="MyXML")
public class MyXML{
       private String a;

       @Element(name="MyElement")
       public void setMyElement(String a){
           this.a=a;
       }

       @Element(name="MyElement")
       public String getMyElement() {
          return a;           
       }
}

Let me know if that works for you.