public   class  TestJAXB {

     public   static   void  main(String[] in){
         new  TestJAXB();
    }

     public  TestJAXB() {
         try  {
            DocumentBuilderFactory  docBuidFact = DocumentBuilderFactory.newInstance();
            Document newDocument = docBuidFact.newDocumentBuilder().newDocument();
            MyObject myObject = getMyObject();            
            JAXBContext context =
                    JAXBContext.newInstance( MyObject. class .getPackage().getName());
            Marshaller marshaller = context.createMarshaller();
            marshaller.marshal(myObject, newDocument);
            saveToFile("file.xml", newDocument);
        }  catch  (Exception ex) {
            ex.printStackTrace();
        }
    }

     private  MyObject getMyObject() {
        MyObject myObject =  new  MyObject();
        myObject.setPk("this PK");
         return  myObject;
    }

     public   static   boolean  saveToFile(String fileName, Document doc){
         try  {
            ByteArrayOutputStream ser = getByteOutputStream(doc);
            DataOutputStream out2 =
                     new  DataOutputStream(
                             new  BufferedOutputStream(
                                     new  FileOutputStream(fileName)));

             byte [] buffer = ser.toByteArray();
            out2.write(buffer);
            out2.close();
             return  true;
        }  catch  (Exception ex) {
            ex.printStackTrace();
             return  false;
        }
    }

     private   static  ByteArrayOutputStream getByteOutputStream(Document xmlResult)  throws 
        TransformerFactoryConfigurationError {
      ByteArrayOutputStream ser =  new  ByteArrayOutputStream();
       try  {
        org.apache.xml.serialize.OutputFormat format =
             new  org.apache.xml.serialize.OutputFormat(org.apache.xml.serialize.Method.XML, "Windows-1251", true );
        org.apache.xml.serialize.XMLSerializer serializer =
             new  org.apache.xml.serialize.XMLSerializer(ser,format);
        serializer.serialize(xmlResult);
      }

       catch  (Exception ex1) {
        ex1.printStackTrace();
      }
       return  ser;
    }
}


 public   class  MyObject {
    
     private  String pk;

     public  MyObject() {
    }

     public   void  setPk(String pk) {
         this .pk = pk;
    }

     public  String getPk() {
         return  pk;
    }
}

 public   class  TestJAXB {

 public   static   void  main(String[] in){
 new  TestJAXB();
}

 public  TestJAXB() {
 try  {
MyObject myObject = getMyObject();
JAXBContext context =
JAXBContext.newInstance(MyObject. class );
context.createMarshaller().marshal(myObject, System.out);
}  catch  (Exception ex) {
ex.printStackTrace();
}
}

 private  MyObject getMyObject() {
MyObject myObject =  new  MyObject();
myObject.setPk("this PK");
 return  myObject;
}

}

 package  test;

 import  javax.xml.bind.annotation.*;

@XmlRootElement
 public   class  MyObject {
 private  String pk;
 public  MyObject() { }

 public   void  setPk(String pk) {
 this .pk = pk;
}
 public  String getPk() {
 return  pk;
}
}