Why IllegalArgumentException is being thrown?

[Arsh Ahmad]

I have an XML Document consisting of SOAP Envelope and SOAP Body elements which is unmarshalled into a SOAP Envelope using the following code:

mEnv = org.apache.soap.Envelope.unmarshall(parentDoc.getDocumentElement());

where parentDoc contains the XML Document. This works fine.

But now I have added code to create a new Document consisting of a SOAP Header element which is added to parentDoc using the following:

parentRoot.insertBefore(hdrNode, bodyElem);

At this point the XML Document looks like the following:

  <?xml version='1.0'?>
<SOAP-ENV:Envelope SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/1999/XMLSchema" xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance">
<SOAP-ENV:Header><m:wsMessageHeader xmlns:m="http://..../common/header/WSMessageHeader/v1">
<m:trackingMessageHeader>
<m:cId>123</m:cId>
<m:aId>8DN</m:aId>
<m:messageDateTimeStamp>2008-08-01T21:42:56.32Z</m:messageDateTimeStamp>
</m:trackingMessageHeader>
</m:wsMessageHeader>
</SOAP-ENV:Header>
<SOAP-ENV:Body>
<m:query xmlns:m="http://.../interfaces/query/v1/query.xsd">
<m:subscriberInformation>
<m:mobileNumber>1234567890</m:mobileNumber>
</m:subscriberInformation>
</m:query>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>  

But when unmarshalling this using the following code again:

mEnv = org.apache.soap.Envelope.unmarshall(parentDoc.getDocumentElement());

throws the following exception:

java.lang.IllegalArgumentException: An 'http://schemas.xmlsoap.org/soap/envelope/:Envelope' element must contain a: 'http://schemas.xmlsoap.org/soap/envelope/:Body' element.

Can anybody tell me why this exception is being thrown, when the XML clearly has the Body element?