The types element describes the different data types that will be used by your web service as inputs and outputs when exchanging messages. In order to achieve as much interoperability as possible and to be platform neutral it is recommended to use XSD as the canonical type system.

The following is an example of the types element in a WSDL 1.1 file. 

<wsdl:types>
    <xs:schema attributeFormDefault = "qualified" elementFormDefault = "qualified" targetNamespace = "http://goj.demo.com">
        <xs:element name = "helloWorld">
            <xs:complexType>
                <xs:sequence>
                    <xs:element minOccurs="0" name = "name" nillable = "true" type = "xs:string"/>
                </xs:sequence>
            </xs:complexType>
        </xs:element>
        <xs:element name = "helloWorldResponse">
            <xs:complexType>
                <xs:sequence>
                    <xs:element minOccurs = "0" name = "return" nillable = "true" type = "xs:string"/>
                </xs:sequence>
            </xs:complexType>
        </xs:element>
    </xs:schema>
</wsdl:types>