At the moment schema and example generation is based on JAXB annotations. So in order to get the schemas and examples generated, your DTOs (Data Transfer Objects) must be annotated with @XMLRootElement used by JAXB.
#XML Example Generation:
XML examples generation is based on the previously generated XML schema and is designed to be the minimal valid XML inferred from the schema. Having said that, if you needed a real life example you should use it as a draft and enrich it with real world values.
JSON Schema and Example are currently generated from XML example