Suppose, I have the following XSD bit:

<xsd:element name="application-policy">
 <xsd:complexType>
 <xsd:sequence>
 <xsd:choice minOccurs="0">
 <xsd:element ref="jbsx:authentication"/>
 <xsd:element ref="jbsx:authentication-jaspi"/>
 </xsd:choice>
 <xsd:element ref="jbsx:authorization" minOccurs="0"/>

 </xsd:sequence>
 </xsd:complexType>
</xsd:element>

I get the following exception:

Caused by: org.jboss.xb.binding.JBossXBRuntimeException: Requested element {urn:
jboss:security-config:5.0}authorization is not allowed in this position in the s
equence. A model group with minOccurs=1 that doesn't contain this element must follow.
 at org.jboss.xb.binding.sunday.unmarshalling.SequenceBinding$1.startElem
ent(SequenceBinding.java:271)
 at org.jboss.xb.binding.sunday.unmarshalling.ModelGroupBinding$Cursor.st
artElement(ModelGroupBinding.java:185)
 at org.jboss.xb.binding.sunday.unmarshalling.SundayContentHandler.startE
lement(SundayContentHandler.java:280)
 at org.jboss.xb.binding.parser.sax.SaxJBossXBParser$DelegatingContentHan
dler.startElement(SaxJBossXBParser.java:381)
 at org.apache.xerces.parsers.AbstractSAXParser.startElement(Unknown Sour
ce)

It seems that XB does not like an xsd:choice with minOccurs/maxOccurs.

My xml looks like:

<jbsx:application-policy name="jboss-web-policy">
 <jbsx:authorization>
 <jbsx:policy-module code="org.jboss.security.authorization.modules.DelegatingAuthorizationModule" flag="required"/>
 </jbsx:authorization>
</jbsx:application-policy>

I am trying to avoid the optional authentication element.