fails to validate minOccurs='0'

[Saha, Sanjeev]

For schema:     <xs:complexType name="Invoice_Type">     <xs:all>       <xs:element name="InvoiceNum" type="INV_NO_Type" minOccurs="0"/>       <xs:element name="InvoiceClass" type="INV_CLASS_Type"/>       <xs:element name="Warehouse" type="WARE_NO_Type"/>     </xs:all>   </xs:complexType>   Where INV_NO_Type is defined as an Integer, I get the following error if I leave out the <InvoiceNum/> tag from the XML.   java.lang.Exception: Xml NOT valid for the following reason(s):             error: Expected element InvoiceNum at the end of the content in element Invoice     However, if I replace <xs:all/> with <xs:sequence/> it seems to work without any problem. Any clues anyone?   Regards, Sanjeev