JAXB doesn't generate all element classes

Question

For a REST service I define the necessary DTOs in XML to generate JAXB object of it. For generation I use the built in option of the Eclipse IDE.

The problem is that the classes don't get generated as expected. Given the XML Schema file below I'm expecting 3 classed to be generated. ImageType, Image and Images. But the Image class for the Image element doesn't get generated. At the moment I don't know what I'm doing wrong.

<?xml version="1.0" encoding="UTF-8"?>
<schema targetNamespace="http://www.company.com/schema/v1/ImageDTO"
    elementFormDefault="qualified" xmlns="http://www.w3.org/2001/XMLSchema"
    xmlns:Q1="http://www.company.com/schema/v1/BusinessObjectDTO"
    xmlns:Q2="http://www.company.com/schema/v1/ImageDTO">

    <import schemaLocation="BusinessObjectDTO.xsd"
        namespace="http://www.company.com/schema/v1/BusinessObjectDTO"></import>

    <complexType name="ImageType" abstract="false">
        <complexContent>
            <extension base="Q1:BusinessObjectType">
                <sequence>
                    <element name="name" type="string" maxOccurs="1" minOccurs="1"></element>
                    <element name="fileName" type="string" maxOccurs="1"
                        minOccurs="1"></element>
                    <element name="thumbnailFileName" type="string" maxOccurs="1"
                        minOccurs="1"></element>
                </sequence>
            </extension>
        </complexContent>
    </complexType>

    <element name="Image" type="Q2:ImageType"></element>

    <element name="Images">
        <complexType>
            <sequence>
                <element name="ImageList" type="Q2:ImageType" maxOccurs="unbounded"
                    minOccurs="0"></element>
            </sequence>
        </complexType>
    </element>
</schema> 

Answer 1

You've defined Image as an element of type ImageType. Image is thus just a name used with that type. The ImageType definition will be turned into a Java class, and when the Image element is refered somewhere in your schema, that'd result in a field of type ImageType annotated as being an XML element with the name Image.

So say that you have...

<element ref="Image" minOccurs="1" maxOccurs="1" />

somewhere in a type definition, that'd result in ...

@XmlElement(name="Image" ...)
ImageType image;

... in the corresponding class.

The reason why Images did get a class definition is because you've defined it as a complexType inline. Image refers to a type, so they're just using the corresponding class. Images has an anonymous type definition, so a class must be generated to capture its structure.