In this code snippet you will learn how to define the order of XML element generated by the JAXB API. To define the element order we need to use the @XmlType annotation in our POJO. This annotation propOrder attribute is where we define what element should come first and which element should be place at the end.

The XML generated by the marshaller below will have the following order: street, city, province, zipcode and country as the last XML element.

package org.kodejava.xml.support;

import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;

public @XmlRootElement(name = "customerAddress")
@XmlType(propOrder = {"street", "city", "province", "zipcode", "country"})
class Address {
    private String street;
    private String city;
    private String province;
    private String country;
    private String zipcode;

    @XmlElement
    public String getStreet() {
        return street;
    }

    public void setStreet(String street) {
        this.street = street;
    }

    @XmlElement
    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    @XmlElement
    public String getProvince() {
        return province;
    }

    public void setProvince(String province) {
        this.province = province;
    }

    @XmlElement
    public String getCountry() {
        return country;
    }

    public void setCountry(String country) {
        this.country = country;
    }

    @XmlElement
    public String getZipcode() {
        return zipcode;
    }

    public void setZipcode(String zipCode) {
        this.zipcode = zipCode;
    }

    @Override
    public String toString() {
        return "Address{" +
                "street='" + street + '\'' +
                ", city='" + city + '\'' +
                ", province='" + province + '\'' +
                ", country='" + country + '\'' +
                ", zipcode='" + zipcode + '\'' +
                '}';
    }
}

Now, let’s create a program to run the marshalling process of the Address POJO to convert it into XML document:

package org.kodejava.xml;

import org.kodejava.xml.support.Address;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;

public class JAXBElementOrder {
    public static void main(String[] args) {
        Address address = new Address();
        address.setStreet("Sunset Road");
        address.setCity("Denpasar");
        address.setProvince("Bali");
        address.setCountry("Indonesia");
        address.setZipcode("80225");

        try {
            JAXBContext context = JAXBContext.newInstance(Address.class);

            Marshaller marshaller = context.createMarshaller();
            marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
            marshaller.marshal(address, System.out);
        } catch (JAXBException e) {
            e.printStackTrace();
        }
    }
}

And it will give you the following output:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<customerAddress>
    <street>Sunset Road</street>
    <city>Denpasar</city>
    <province>Bali</province>
    <zipcode>80225</zipcode>
    <country>Indonesia</country>
</customerAddress>

Maven Dependencies

<dependencies>
    <dependency>
        <groupId>javax.xml.bind</groupId>
        <artifactId>jaxb-api</artifactId>
        <version>2.3.1</version>
    </dependency>
    <dependency>
        <groupId>com.sun.xml.bind</groupId>
        <artifactId>jaxb-ri</artifactId>
        <version>2.3.5</version>
        <type>pom</type>
    </dependency>
</dependencies>

In the following code snippet you will learn how to change the default root element name of the XML generated by the JAXB API. By default, the name of the class is use as the root element name. To change the root element name we can use the name property of the @XmlRootElement annotation. In the Customer model below we change the root element name into cust.

package org.kodejava.xml;

import org.kodejava.xml.support.Address;

import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;

@XmlRootElement(name = "cust")
@XmlType(propOrder = {"id", "name", "address"})
public class Customer {
    private Integer id;
    private String name;
    private Address address;

    @XmlElement
    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

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

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

    @XmlElement
    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }
}

package org.kodejava.xml.support;

public class Address {
    private String street;
    private String city;
    private String province;
    private String zipcode;
    private String country;

    // Getters & Setters
}

package org.kodejava.xml;

import org.kodejava.xml.support.Address;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;

public class JAXBCustomRootElement {
    public static void main(String[] args) {
        Customer customer = new Customer();
        customer.setId(1);
        customer.setName("Johnny Mnemonic");

        Address address = new Address();
        address.setStreet("Sunset Road");
        address.setCity("Denpasar");
        address.setProvince("Bali");
        address.setZipcode("80225");
        address.setCountry("Indonesia");
        customer.setAddress(address);

        try {
            JAXBContext context = JAXBContext.newInstance(Customer.class);
            Marshaller marshaller = context.createMarshaller();
            marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
            marshaller.marshal(customer, System.out);
        } catch (JAXBException e) {
            e.printStackTrace();
        }
    }
}

When we convert this POJO to XML using JAXB API we will get the following result:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<cust>
    <id>1</id>
    <name>Johnny Mnemonic</name>
    <address>
        <city>Denpasar</city>
        <country>Indonesia</country>
        <province>Bali</province>
        <street>Sunset Road</street>
        <zipcode>80225</zipcode>
    </address>
</cust>

Maven Dependencies

<dependencies>
    <dependency>
        <groupId>javax.xml.bind</groupId>
        <artifactId>jaxb-api</artifactId>
        <version>2.3.1</version>
    </dependency>    
    <dependency>
        <groupId>com.sun.xml.bind</groupId>
        <artifactId>jaxb-ri</artifactId>
        <version>2.3.5</version>
        <type>pom</type>
    </dependency>
</dependencies>