ValidateObjectResponse response = (ValidateObjectResponse) webServiceTemplate.marshalSendAndReceive(request);

<SOAP-ENV:Envelope xmlns:SOAPENV="http://schemas.xmlsoap.org/soap/envelope/">
    <SOAP-ENV:Header/>
    <SOAP-ENV:Body>
        <ns2:validateObject xmlns:ns2="http://ws.validator.sch.gazelle.ihe.net/" xmlns=""><base64ObjectToValidate>Cgo8P3ht...
    </SOAP-ENV:Body>
</SOAP-ENV>

java.lang.IllegalArgumentException: Cannot bind a prefix to the empty namespace name
at org.apache.axiom.om.impl.dom.ElementImpl.declareNamespace(ElementImpl.java:754)
at org.apache.axiom.om.impl.dom.ElementImpl.declareNamespace(ElementImpl.java:778)
at org.apache.axiom.om.impl.dom.ElementImpl.setAttributeNS(ElementImpl.java:559)
at com.sun.xml.bind.marshaller.SAX2DOMEx.startElement(SAX2DOMEx.java:163)
at com.sun.xml.bind.v2.runtime.output.SAXOutput.endStartTag(SAXOutput.java:124)
at com.sun.xml.bind.v2.runtime.XMLSerializer.endAttributes(XMLSerializer.java:302)
at com.sun.xml.bind.v2.runtime.XMLSerializer.childAsSoleContent(XMLSerializer.java:588)
at com.sun.xml.bind.v2.runtime.ClassBeanInfoImpl.serializeRoot(ClassBeanInfoImpl.java:312)
at com.sun.xml.bind.v2.runtime.XMLSerializer.childAsRoot(XMLSerializer.java:490)
at com.sun.xml.bind.v2.runtime.MarshallerImpl.write(MarshallerImpl.java:328)
at com.sun.xml.bind.v2.runtime.MarshallerImpl.marshal(MarshallerImpl.java:257)
at org.springframework.oxm.jaxb.Jaxb2Marshaller.marshal(Jaxb2Marshaller.java:680)
at org.springframework.ws.support.MarshallingUtils.marshal(MarshallingUtils.java:81)
at org.springframework.ws.client.core.WebServiceTemplate$2.doWithMessage(WebServiceTemplate.java:399)
at org.springframework.ws.client.core.WebServiceTemplate.doSendAndReceive(WebServiceTemplate.java:590)
at org.springframework.ws.client.core.WebServiceTemplate.sendAndReceive(WebServiceTemplate.java:555)
at org.springframework.ws.client.core.WebServiceTemplate.marshalSendAndReceive(WebServiceTemplate.java:390)
at org.springframework.ws.client.core.WebServiceTemplate.marshalSendAndReceive(WebServiceTemplate.java:383)
at org.springframework.ws.client.core.WebServiceTemplate.marshalSendAndReceive(WebServiceTemplate.java:373)

<?xml version='1.0' encoding='UTF-8'?>
<wsdl:definitions xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/" xmlns:tns="http://ws.validator.sch.gazelle.ihe.net/"
              xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/"
              name="GazelleObjectValidatorService" targetNamespace="http://ws.validator.sch.gazelle.ihe.net/">
    <wsdl:types>
        <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:tns="http://ws.validator.sch.gazelle.ihe.net/"
               attributeFormDefault="unqualified" elementFormDefault="unqualified"
               targetNamespace="http://ws.validator.sch.gazelle.ihe.net/">
        <xs:element name="about" type="tns:about"/>
        <xs:element name="aboutResponse" type="tns:aboutResponse"/>
        <xs:element name="getAllAvailableObjectTypes" type="tns:getAllAvailableObjectTypes"/>
        <xs:element name="getAllAvailableObjectTypesResponse" type="tns:getAllAvailableObjectTypesResponse"/>
        <xs:element name="getAllSchematrons" type="tns:getAllSchematrons"/>
        <xs:element name="getAllSchematronsResponse" type="tns:getAllSchematronsResponse"/>
        <xs:element name="getSchematronByName" type="tns:getSchematronByName"/>
        <xs:element name="getSchematronByNameResponse" type="tns:getSchematronByNameResponse"/>
        <xs:element name="getSchematronsForAGivenType" type="tns:getSchematronsForAGivenType"/>
        <xs:element name="getSchematronsForAGivenTypeResponse" type="tns:getSchematronsForAGivenTypeResponse"/>
        <xs:element name="validateObject" type="tns:validateObject"/>
        <xs:element name="validateObjectResponse" type="tns:validateObjectResponse"/>