How to find out which JAXB implementation is used in your code

When using WildFly or JBoss EAP, the JAXB implementation is defined by the following specification in module.xml:

<module name="javax.xml.bind.api" xmlns="urn:jboss:module:1.7">


    <dependencies>
        <module name="javax.activation.api" export="true"/>
        <module name="javax.xml.stream.api"/>
        <module name="com.sun.xml.bind" services="import"/>
        <module name="javax.api"/>
    </dependencies>

    <resources>
        <resource-root path="jboss-jaxb-api_2.3_spec-1.0.1.Final-redhat-1.jar"/>
    </resources>
</module>

 In order to check the actual JAXB implementation, you can just create a new Instance of JAXBContext and execute a getClass() againsts its name:

@WebServlet(value = "/jaxb" )
public class DemoServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse res) {
        try {
            PrintWriter out = res.getWriter();
            JAXBContext jc = JAXBContext.newInstance(Employee.class);
            String jcClassName = jc.getClass().getName();
            out.println(jcClassName);
        
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
 
}


@XmlRootElement
public class Employee {
    private int id;
    private String name;
    private float salary;

    public Employee() {}
    public Employee(int id, String name, float salary) {
        super();
        this.id = id;
        this.name = name;
        this.salary = salary;
    }
    @XmlAttribute
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    @XmlElement
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    @XmlElement
    public float getSalary() {
        return salary;
    }
    public void setSalary(float salary) {
        this.salary = salary;
    }
}

If you want to check the exact version of your JAXB implementation, the following code will do it:

if (jc instanceof com.sun.xml.bind.v2.runtime.JAXBContextImpl) {
                out.println("JAXB Version: " +
                        ((com.sun.xml.bind.v2.runtime.JAXBContextImpl) jc).getBuildId());
}

Furthermore, if you want to check the JAXB implementation for a specific class, then you can do it as follows:

/**
    * Print the JAXB Implementation information
    */
public static void outputJaxpImplementationInfo() {
       logger.debug(getImplementationInfo("DocumentBuilderFactory", DocumentBuilderFactory.newInstance().getClass()));
       logger.debug(getImplementationInfo("XPathFactory", XPathFactory.newInstance().getClass()));
       logger.debug(getImplementationInfo("TransformerFactory", TransformerFactory.newInstance().getClass()));
       logger.debug(getImplementationInfo("SAXParserFactory", SAXParserFactory.newInstance().getClass()));
}

/**
    * Get the JAXB implementation information for a particular class
    * @param componentName
    * @param componentClass
    * @return
    */
private static String getImplementationInfo(String componentName, Class componentClass) {
       CodeSource source = componentClass.getProtectionDomain().getCodeSource();
       return MessageFormat.format(
               "{0} implementation: {1} loaded from: {2}",
               componentName,
               componentClass.getName(),
               source == null ? "Java Runtime" : source.getLocation());
}

Building JAXB applications using Java 11 or newer

According to the release-notes, Java 11 removed the Java EE modules:

java.xml.bind (JAXB)- REMOVED

• Java 8 – OK
• Java 9 – DEPRECATED
• Java 10 – DEPRECATED
• Java 11 – REMOVED

<dependency>
  <groupId>javax.xml.bind</groupId>
  <artifactId>jaxb-api</artifactId>
  <version>2.3.0</version>
</dependency>
<dependency>
  <groupId>com.sun.xml.bind</groupId>
  <artifactId>jaxb-core</artifactId>
  <version>2.3.0</version>
</dependency>
<dependency>
  <groupId>com.sun.xml.bind</groupId>
  <artifactId>jaxb-impl</artifactId>
  <version>2.3.0</version>
</dependency>

<dependency>
  <groupId>jakarta.xml.bind</groupId>
  <artifactId>jakarta.xml.bind-api</artifactId>
  <version>2.3.3</version></dependency>