Here is DecimalType, which is a complexType with simpleContent that extends a simpleType, xs:decimal:
<xs:complexType name="DecimalType">
<xs:simpleContent>
<xs:extension base="xs:decimal">
<xs:attribute ref="xs:decimal">
</xs:attribute>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
Here is AngleMeasureType, which is a complexType with complexContent that extends DecimalType by adding another attribute:
<xs:complexType name="AngleMeasureType">
<xs:complexContent>
<xs:extension base="tns:DecimalType">
<xs:attribute name="angleUOM" type="xs:string">
</xs:attribute>
</xs:extension>
</xs:complexContent>
</xs:complexType>
This process of changing from simpleContent (in DecimalType) to complexContent (in AngleMeasureType), while only adding attributes to the content, breaks the XmlBeans schema type system.
This has been tested with XmlBeans versions 2.2 and 2.3.
The resolution is to change AngleMeasureType to have simpleContent, as follows:
<xs:complexType name="AngleMeasureType">
<xs:simpleContent>
<xs:extension base="tns:DecimalType">
<xs:attribute name="angleUOM" type="xs:string">
</xs:attribute>
</xs:extension>
</xs:simpleContent>
</xs:complexType>
The error appears when calling xobj.validate(), or with the xsb dumper:
Unknown simple type variety
Exception in thread "main" java.lang.IllegalStateException: Unknown simple type variety
at org.apache.xmlbeans.impl.tool.XsbDumper.error(XsbDumper.java:149)
at org.apache.xmlbeans.impl.tool.XsbDumper.dumpTypeFileData(XsbDumper.java:1009)
