Today in Studio if a schema definition has a required field, when we generate the jar and examine the xsd, that field has the 'nillable' property but not the 'nxsv:nillable' property:
<xs:element name="string1" type="xs:string" nillable="false"/>
'nxsv:nillable' is required for validation.
This is observable with target version 2021 or 2023