The main source for metadata structure generation are annotated entity classes.

Entity class will be present in the metadata in the following cases:

All entities inside same root package are put into the same MetaModel instance, which is given the name of this package. Entities within the same MetaModel can contain arbitrary references to each other. References between entities from different meta-models can be created in the order of declaration of metadata.xml files in cuba.metadataConfig property.

Entity attribute will be present in metadata if:

Metaclass and metaproperty parameters are determined on the base of the listed annotations parameters as well as field types and class methods. Besides, if an attribute does not have write access method (setter), it becomes immutable (read-only).