Java HTML / XML How to - Get on null value in JAXB generated model

Question

We would like to know how to get on null value in JAXB generated model.
Answer

/* ww w  . j  a v  a  2  s.  co m*/

import java.io.StringReader;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

public class Main {

  public static void main(String[] args) throws Exception {
    JAXBContext jc = JAXBContext.newInstance(Address.class);

    StringReader xml = new StringReader("<Address><Name>Test</Name></Address>");
    Unmarshaller unmarshaller = jc.createUnmarshaller();
    Address address = (Address) unmarshaller.unmarshal(xml);

    System.out.println(address.getPostalAddress().getState());

    Marshaller marshaller = jc.createMarshaller();
    marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
    marshaller.marshal(address, System.out);
  }

  @XmlRootElement(name = "Address")
  public static class Address {

    private String name;
    private PostalAddress postalAddress;

    @XmlElement(name = "Name")
    public String getName() {
      return name;
    }

    public void setName(String name) {
      this.name = name;
    }

    @XmlElement(name = "PostalAddress")
    public PostalAddress getPostalAddress() {
      if (null == postalAddress) {
        postalAddress = new PostalAddress();
      }
      return postalAddress;
    }

    public void setPostalAddress(PostalAddress postalAddress) {
      this.postalAddress = postalAddress;
    }

  }

  public static class PostalAddress {

    private String state;

    @XmlElement(name = "State")
    public String getState() {
      return state;
    }

    public void setState(String state) {
      this.state = state;
    }
  }
}