I suggest that you determine what is the object that you want to pass from the Endpoint implementation back to the Android client.
In your case, you want the id
and the description
only for the Department
entity. Though it would be some additional work, I would recommend that you define separate Data Transfer Objects that are separate from your actual Entity objects. It will lend itself well to future enhancements/changes and promote loose coupling.
So you could define another Java class say DepartmentDTO or something like that and in that class simply have the id and description fields only. You can then change the Endpoint class signature to use the DepartmentDTO instead of the Department entity.