What does `extra classes` parameter from `Java2WSDL` do? - wsdl

Question

Does anyone know what extra classes parameter from Java2WSDL tool mean?
Java2DSDL Reference
I am looking to answer this question, but have no success.

Answer 1

It is used to include those types in WSDL definition whose parents appears as return types or parameters. Consider very simple example:
public class DemoService {
public Animal pickRandomAnimal() {
return new Dog(); // or any other animal
}
}
.. where Animal is an interface. At a WSDL generation time Axis2 will not be able to automatically trace all possible implementations of Animal that you might expect to be returned. Without extraClasses you'll get something like this:
<xs:schema attributeFormDefault="qualified" elementFormDefault="qualified" targetNamespace="http://demo.com/xsd">
<xs:complexType name="Animal">
<xs:sequence>
<xs:element minOccurs="0" name="animalName" nillable="true" type="xs:string"/>
</xs:sequence>
</xs:complexType>
</xs:schema>
.. and if you add extraClasses="com.demo.Dog", you'll cover all types you need in your WSDL schema part:
<xs:schema attributeFormDefault="qualified" elementFormDefault="qualified" targetNamespace="http://demo.com/xsd">
<xs:complexType name="Animal">
<xs:sequence>
<xs:element minOccurs="0" name="animalName" nillable="true" type="xs:string"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="Dog">
<xs:sequence>
<xs:element minOccurs="0" name="animalName" nillable="true" type="xs:string"/>
</xs:sequence>
</xs:complexType>
</xs:schema>