How to create a pojo from xml for jaxb ( Unmarshalling)

Question

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

<STATUS_UPDATE>
    <UPDATES_COUNTER>2</UPDATES_COUNTER>
    <LETTERS>
        <LETTER>
            <LETTER_KEY>key1</LETTER_KEY>
            <STATUS>status1</STATUS>
        </LETTER>
        <LETTER>
            <LETTER_KEY>key2</LETTER_KEY>
            <STATUS>status2</STATUS>
        </LETTER>
    </LETTERS>
</STATUS_UPDATE>

So i have this xml. Im trying to create a pojo from it.

@XmlRootElement(name = "STATUS_UPDATE")
public class StatusUpdate {

    private int updatesCounter;


    List<Letter> letters;

    public StatusUpdate(){
        letters = new ArrayList<Letter>();
    }

    public StatusUpdate(int updatesCounter, List<Letter> letters){
        super();
        this.updatesCounter = updatesCounter;
        this.letters =  letters;
    }

    @XmlElement(name="LETTERS")
    public List<Letter> getLetters() {
        return letters;
    }

    public void setLetters(List<Letter> letters) {
        this.letters = letters;
    }
    @XmlElement(name="UPDATES_COUNTER")
    public int getUpdatesCounter() {
        return updatesCounter;
    }

    public void setUpdatesCounter(int updatesCounter) {
        this.updatesCounter = updatesCounter;
    }

}

And letter class

@XmlRootElement(name = "LETTER")
public class Letter {


    public Letter(){

    }

    public Letter(String letterKey,String status){
        this.letterKey = letterKey;
        this.status = status;
    }
    String letterKey;
    String status;

    @XmlElement(name="LETTER_KEY")
    public String getLetterKey() {
        return letterKey;
    }
    public void setLetterKey(String letterKey) {
        this.letterKey = letterKey;
    }
    @XmlElement(name="STATUS")
    public String getStatus() {
        return status;
    }
    public void setStatus(String status) {
        this.status = status;
    }
}

and this code snipper wont seem to do the job. i get no errors, code runs, i get a 2 in my updateCounter variable, but my list is empty with only one letter object, with both variables null.

File file = new File("myFile.xml");
JAXBContext jaxbContext = JAXBContext.newInstance(StatusUpdate.class ); 
Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
StatusUpdate msgObject = (StatusUpdate) jaxbUnmarshaller.unmarshal(file);

I've been reading the documentations and examples, but most of them are either written to match variable names and xml elemenets (which i dont want to) or are either not helpfull to me. Any ideas? I have a feeling i'm very close to my goal but i can't seem to grasp what i'm missing.

Answer 1

You need to add @XmlElementWrapper(name = "LETTERS") annotation to getLetters() method like this

@XmlElementWrapper(name = "LETTERS")
@XmlElement(name = "LETTER")
public List<Letter> getLetters() {
    return letters;
}