I have what seems to be a correct piece of SOAP being sent to JBossWS 1.0.4 that causes a binding exception. This only occurs when I send 2 different sub-class/derived types in the same container type. Sending each type independently (or several instances of the same type) works fine. In my example I have a Transaction type that contains an unbound number of Atoms, where Atom is an abstract type. There are 2 derivative of Atom, AtomType1 and AtomType2 which each extend Atom and add an additional sub-element element unique to the specialised type. (You can assume the namespaces/jax-rpc mapping is correct as when used independently from each other, the derived types bind fine.) My Types... | <complexType abstract="true" name="Atom"> | <sequence> | <element name="atom_id" type="nonNegativeInteger" /> | <element name="name" nillable="true" type="string" /> | </sequence> | </complexType> | | <complexType name="Transaction"> | <sequence> | <element maxOccurs="unbounded" name="atom" type="myns:Atom" /> | </sequence> | </complexType> | | | <complexType name="AtomType1"> | <complexContent> | <extension base="myns:Atom"> | <sequence> | <element name="atom_type_1_value" type="unsignedLong" /> | </sequence> | </extension> | </complexContent> | </complexType> | | <complexType name="AtomType2"> | <complexContent> | <extension base="myns:Atom"> | <sequence> | <element name="atom_type_2_value" type="unsignedLong" /> | </sequence> | </extension> | </complexContent> | </complexType> First example which is processed fine, and proves the type is bound correctly. Single Atom in the Transaction <?xml version="1.0" encoding="UTF-8"?> | <env:Envelope | xmlns:env="http://schemas.xmlsoap.org/soap/envelope/" | xmlns:xsd="http://www.w3.org/2001/XMLSchema" | xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" | xmlns:enc="http://schemas.xmlsoap.org/soap/encoding/" | xmlns:ns0="http://mynamespace"> | | <env:Body> | <ns0:update> | <Transaction_1> | | <atom xmlns:ans1="http://mynamespace" xsi:type="ans1:AtomType2"> | <atom_id>1</atom_id> | <name>myName2</name> | <atom_type_2_value>2</atom_type_2_value> | </atom> | | </Transaction_1> | </ns0:update> | </env:Body> | </env:Envelope> The next Transaction contains 2 different Atom derived types, and fails processing with this exception Error: anonymous wrote : org.jboss.ws.binding.BindingException: org.jboss.ws.jbossxb.UnmarshalException: Failed to parse source: Requested element atom_type_2_value is not allowed in this position in the sequence. A model group with minOccurs=1 that doesn't contain this element must follow. <?xml version="1.0" encoding="UTF-8"?> | <env:Envelope | xmlns:env="http://schemas.xmlsoap.org/soap/envelope/" | xmlns:xsd="http://www.w3.org/2001/XMLSchema" | xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" | xmlns:enc="http://schemas.xmlsoap.org/soap/encoding/" | xmlns:ns0="http://mynamespace"> | | <env:Body> | <ns0:update> | <Transaction_1> | | <atom xmlns:ans1="http://mynamespace" xsi:type="ans1:AtomType1"> | <atom_id>1</atom_id> | <name>myName</name> | <atom_type_1_value>2</atom_type_1_value> | </atom> | | <atom xmlns:ans1="http://mynamespace" xsi:type="ans1:AtomType2"> | <atom_id>2</atom_id> | <name>myName2</name> | <atom_type_2_value>2</atom_type_2_value> | </atom> | | </Transaction_1> | </ns0:update> | </env:Body> | </env:Envelope> Just for a test, I switched the order of the Atoms in the transaction and note that the binding exception is now accredited to the other derived type Error: anonymous wrote : org.jboss.ws.binding.BindingException: org.jboss.ws.jbossxb.UnmarshalException: Failed to parse source: Requested element atom_type_1_value is not allowed in this position in the sequence. A model group with minOccurs=1 that doesn't contain this element must follow. <?xml version="1.0" encoding="UTF-8"?> | <env:Envelope | xmlns:env="http://schemas.xmlsoap.org/soap/envelope/" | xmlns:xsd="http://www.w3.org/2001/XMLSchema" | xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" | xmlns:enc="http://schemas.xmlsoap.org/soap/encoding/" | xmlns:ns0="http://mynamespace"> | | <env:Body> | <ns0:update> | <Transaction_1> | | <atom xmlns:ans1="http://mynamespace" xsi:type="ans1:AtomType2"> | <atom_id>1</atom_id> | <name>myName</name> | <atom_type_1_value>2</atom_type_1_value> | </atom> | | <atom xmlns:ans1="http://mynamespace" xsi:type="ans1:AtomType1"> | <atom_id>2</atom_id> | <name>myName2</name> | <atom_type_2_value>2</atom_type_2_value> | </atom> | | </Transaction_1> | </ns0:update> | </env:Body> | </env:Envelope> The final Transaction contains 2 atoms of the same derived type - and is processed fine. <?xml version="1.0" encoding="UTF-8"?> | <env:Envelope | xmlns:env="http://schemas.xmlsoap.org/soap/envelope/" | xmlns:xsd="http://www.w3.org/2001/XMLSchema" | xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" | xmlns:enc="http://schemas.xmlsoap.org/soap/encoding/" | xmlns:ns0="http://mynamespace"> | | <env:Body> | <ns0:update> | <Transaction_1> | | <atom xmlns:ans1="http://mynamespace" xsi:type="ans1:AtomType1"> | <atom_id>1</atom_id> | <name>myName</name> | <atom_type_1_value>2</atom_type_1_value> | </atom> | | <atom xmlns:ans1="http://mynamespace" xsi:type="ans1:AtomType1"> | <atom_id>2</atom_id> | <name>myName2</name> | <atom_type_2_value>2</atom_type_2_value> | </atom> | | </Transaction_1> | </ns0:update> | </env:Body> | </env:Envelope> Worth raising a bug? Regards - J View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4019863#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...