Up-to-date Documentation on JAXB Bindings for XSD and DTD

Question

I'm trying to generate classes from XSD and DTD files while adding some customizations (have the generated classes implement an interface).

I found this thread about XSD bindings, however, it no longer functions.

Let's say I use a dummy bindings.xjb:

<jxb:bindings version="1.0" 
  xmlns:jxb="http://java.sun.com/xml/ns/jaxb" 
  xmlns:xs="http://www.w3.org/2001/XMLSchema" 
  xmlns:xjc="http://java.sun.com/xml/ns/jaxb/xjc" 
  jxb:extensionBindingPrefixes="xjc">
</jxb:bindings>

Calling xjc with:

xjc -b bindings.xjb example.xsd

XJC will complaint that the namespace http://java.sun.com/xml/ns/jaxb is not supported.

Looking at Oracle's site, I can only find Customizing JAXB Bindings which didn't say much about the namespaces other than:

<jxb:bindings version="1.0" 
    xmlns:jxb="http://java.sun.com/xml/ns/jaxb" 
    xmlns:xs="http://www.w3.org/2001/XMLSchema">

which is also not working.

For DTD instead of XSD, This other thread mentioned that when using DTD, the bindings file is completely different and should look like this:

<?xml version="1.0"?>
    <xml-java-binding-schema version="1.0ea2">
       <element name="us-patent-grant" type="class" root="true"></element>
    </xml-java-binding-schema>

Searching with the root element's name, I cannot find documentation on its syntax.

Where are the documentation for the binding file used in xjc -b [file] option for both XSD and DTD?

EDIT: I think I've found the documentation for XSD here: https://javaee.github.io/jaxb-v2/doc/user-guide/ch03.html

But in my case, I only have a DTD, and that page didn't cover xml-java-binding-schema.

KC Wong · Accepted Answer · 2023-05-31T07:25:24.030

I think I've found it: http://xml.coverpages.org/jaxb0530spec.pdf

The PDF is linked at the bottom of this page from Oracle: https://docs.oracle.com/cd/E17802_01/webservices/webservices/docs/1.6/jaxb/vendorSchemaLangs.html#dtd

For XSD it is: https://javaee.github.io/jaxb-v2/doc/user-guide/ch03.html

Edit: Turns out there are more. First there are multiple JAXB maven plugins implemented by different parties. Not all of them support plugins and they expect different things in the binding XJB file.

I ended up using this one, which has plugins for adding an interface:

<groupId>org.jvnet.jaxb2.maven2</groupId>
                <artifactId>maven-jaxb2-plugin</artifactId>
                <version>0.15.3</version>

The configuration is:

    <plugin>
        <!-- There are multiple JAXB plugins... but only this one supports the use of extensions -->
        <groupId>org.jvnet.jaxb2.maven2</groupId>
        <artifactId>maven-jaxb2-plugin</artifactId>
        <version>0.15.3</version>
        <executions>
            <execution>
                <goals>
                    <goal>generate</goal>
                </goals>
            </execution>
        </executions>
        <configuration>
            <extension>true</extension>
            <args>
                <arg>-Xinheritance</arg>
            </args>
                            <schemas>
                <schema>
                    <fileset>
                        <directory>${project.basedir}/src/main/resources/schema</directory>
                        <includes>
                            <include>workflow_2_8.xsd</include>
                        </includes>
                    </fileset>
                </schema>
            </schemas>
            <bindings>
                <binding>
                    <fileset>
                        <directory>${project.basedir}/src/main/resources/schema</directory>
                        <includes>
                            <include>xsd_bindings.xjb</include>
                        </includes>
                    </fileset>
                </binding>
            </bindings>
            <generateDirectory>${project.build.directory}/generated-sources/jaxb</generateDirectory>
            <plugins>
                <plugin>
                    <groupId>org.jvnet.jaxb2_commons</groupId>
                    <artifactId>jaxb2-basics</artifactId>
                    <version>0.6.4</version>
                </plugin>
            </plugins>
        </configuration>
    </plugin>

And the bindings I use:

<?xml version="1.0"?>
<jxb:bindings version="1.0"
    xmlns:jxb="http://java.sun.com/xml/ns/jaxb"
    xmlns:xs="http://www.w3.org/2001/XMLSchema"
    xmlns:xjc="http://java.sun.com/xml/ns/jaxb/xjc"
    xmlns:inheritance="http://jaxb2-commons.dev.java.net/basic/inheritance"
    jxb:extensionBindingPrefixes="xjc">
    
    <jxb:bindings schemaLocation="workflow_2_8.xsd">
    
        <!-- Set output package -->
        <jxb:schemaBindings>
            <jxb:package name="output package name here"/>
        </jxb:schemaBindings>

        <!-- Make generated classes implement interface -->
        <jxb:bindings multiple="true" node="//xs:element/xs:complexType">
            <inheritance:implements>Interface name here
            </inheritance:implements>
        </jxb:bindings>
    
    </jxb:bindings>
    
</jxb:bindings>

Also need yet another plugin to add the generated source files to source path:

<plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>build-helper-maven-plugin</artifactId>
                <version>1.8</version>
                <executions>
                    <execution>
                        <id>add-source</id>
                        <phase>generate-sources</phase>
                        <goals>
                            <goal>add-source</goal>
                        </goals>
                        <configuration>
                            <sources>
                                <source>${project.build.directory}/generated-sources/jaxb</source>
                            </sources>
                        </configuration>
                    </execution>
                </executions>
            </plugin>

Rick O'Sullivan · Answer 2 · 2023-06-06T00:41:15.073

This zip is an exploration of using DTD to generate JAXB classes.

You may want to upgrade from the javax dependencies to the more current jakarta dependencies, the source/target (release) compatibility for the projects below is at Java 11, up from Java 8. And, JDK 17 is used for the build. JAXB dependencies are at version 4.x for Jakarta EE 10.

hisrc-higherjaxb-maven-plugin - Maven plugin for JAXB 4.x forked from maven-jaxb2-plugin.
hisrc-basicjaxb-plugins - JAXB 4.x plugins forked from jaxb2-basics.

Here hisrc-higherjaxb-sample-jaxbplugins-2.1.0-mvn-src.zip is a sample project and to learn more see HiSrc Sample JAXB Plugins.

Note: The 4.x release of the JAXB API, RI and ZIP continues to use the latest JAXB Schema Binding 3.0 Specification.

Disclaimer: I am the maintainer for the forked HiSrc projects.

Up-to-date Documentation on JAXB Bindings for XSD and DTD

2 Answers2