JAXB unmarshall annotations question

@XmlRootElement 
class Foo {
  @XmlElement
  String a;
  @XmlElement(required=true)
  String b;
 
protected SubClass c;
 
public SubClass getSubClass(){
     return c;
}
 
public SubClass setSubClass(SubClass sc){
    this.c = sc;
}                           
 
}
 
-------------------------------------------------------
public class SubClass
-------------------------------------------------------
protected long[] local_long ;
 
public  long[] get_long(){
   return local_long;
 }
 
public void set_long(long[] param){
   this.local_long = param;                         
}                        
 
-------------------------------------------------------
myJaxb.java
-------------------------------------------------------
 
    JAXBContext jc = JAXBContext.newInstance(new Class[] {jaxb.Foo.class});
      
          Unmarshaller u = jc.createUnmarshaller();
      
          Foo fooObj = (Foo)u.unmarshal(
              new FileInputStream( "foo.xml" ) ); 
 
---------------------------------------
foo.xml
----------------------------------------
<?xml version="1.0" encoding="UTF-8"?>
<foo>
         <a>1</a>
         <b>2</b>
         <subClass>
               <long>13</long>
               <long>44</long>
         </subClass>
</foo>