Adding namespaces to root element of xml using jaxb

Question

I am creating an xml file whose root elemenet structure shuould be like:

Answer 1

In the older Jaxb you can specify additional namespaces using @XmlSeeAlso and in the newer Jaxb you can use @XmlNs in package-info.java see this answer: https://stackoverflow.com/a/63559294/447503

Answer 2

Below is some demo code that will produce the XML you are looking for. You can use the Marshaller.JAXB_SCHEMA_LOCATION property to specify the schemaLocation this will cause the http://www.w3.org/2001/XMLSchema-instance namespace to be automatically declared.

Demo

package myproject.myapp;

import javax.xml.bind.*;

public class Demo {

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

        RootElement rootElement = new RootElement();

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.setProperty(Marshaller.JAXB_SCHEMA_LOCATION, "http://www.mysite.com/abc.xsd");
        marshaller.marshal(rootElement, System.out);
    }

}

Output

Below is the output from running the demo code.

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<RootElement xmlns="http://www.mysite.com" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.mysite.com/abc.xsd"/>

package-info

This is the package-info class from your question.

@XmlSchema(
    namespace = "http://www.mysite.com",
    elementFormDefault = javax.xml.bind.annotation.XmlNsForm.QUALIFIED
)
package myproject.myapp;

import javax.xml.bind.annotation.*;

RootElement

Below is a simplified version of your domain model:

package myproject.myapp;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name="RootElement")
public class RootElement {

}