Java application (university-like difficulty)

I'm requested to do a sample project of a "school library" in various platform/languages and as a front-ender I want to leave the Java one to a developer with more knowledge than me about the technology. The project can be written in Swing or JavaFX, it is consisted of 2 type of users (Librarian and Reader). It has to be a client-server application capable of serving more than one client at time. It needs a persistence layer in PostgreSQL and it needs to send email with provided SMTP settings and credentials (send mail for register users). The public interface should be documented with JavaDoc (the private code doesn't need to). The project cannot use Spring, but can include some common Java libs. It needs maven commands to start the application and the DB and possibly some script (maven or shell) to populate the database with fake data. The code should be the easiest possible because an UML documentation should be added and ER diagrams too (we can discuss if it is up to you or not).