Unmarshalling returned null object from a successfully marshalled XML

i have the following classes which is marshalled as an XML

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

    <customer id="100">

        <age>21</age>

        <hobbies>

            <hobby>

        <cost>sd</cost>

        <name>na</name>

            </hobby>

            <hobby>

                <cost>sd</cost>

                <name>nb</name>

            </hobby>

        </hobbies>

        <name>test</name>

    </customer>

However, when i tried to unmarshall, I can only create the customer object but not hobby, which returns null Am i doing something wrong here? The problem seems to be with the XML hierarchy?

package com.mytest.jxb;



import java.util.ArrayList;

import java.util.List;



import javax.xml.bind.annotation.XmlAttribute;

import javax.xml.bind.annotation.XmlElement;

import javax.xml.bind.annotation.XmlElementRef;

import javax.xml.bind.annotation.XmlElementWrapper;

import javax.xml.bind.annotation.XmlRootElement;

import javax.xml.bind.annotation.XmlSeeAlso;



@XmlRootElement(name="customer")

@XmlSeeAlso({Hobby.class})

public class Customer {



    String name;

    int age;

    int id;

    @XmlElementRef

    private List<Hobby> hobbyList = new ArrayList<Hobby>();



    public Customer(){

        //hobbyList = new ArrayList<Hobby>();

    }



    //@XmlElement

    public String getName() {

        return name;

    }



    @XmlElement

    public void setName(String name) {

        this.name = name;

    }



    //@XmlElement

    public int getAge() {

        return age;

    }



    @XmlElement

    public void setAge(int age) {

        this.age = age;

    }

    //@XmlAttribute

    public int getId() {

        return id;

    }



    @XmlAttribute

    public void setId(int id) {

        this.id = id;

    }

    public void addHobby(Hobby h) {

        hobbyList.add(h);

    }

    @XmlElementWrapper(name="hobbies")

    @XmlElement(name = "hobby")

    public List<Hobby> getHobbies(){

        return hobbyList;

    }

}



package com.mytest.jxb;



import javax.xml.bind.annotation.XmlAttribute;

import javax.xml.bind.annotation.XmlElement;

import javax.xml.bind.annotation.XmlRootElement;



@XmlRootElement

class Hobby {



    private String name;

    private String cost;



    public Hobby(){

    }



    public Hobby(String name, String cost){

        this.name = name;

        this.cost = cost;

    }

    //@XmlElement

    public void setName(){

        this.name = name;

    }

    @XmlElement

    public String getName(){

        return name;

    }

    //@XmlElement

    public void setCost(){

        this.cost = cost;

    }

    @XmlElement

    public String getCost(){

        return cost;

    }

}